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diff --git a/doc/sed.info b/doc/sed.info index 38235da..6caa43c 100644 --- a/doc/sed.info +++ b/doc/sed.info @@ -1,1059 +1,1176 @@ -This is ../../doc/sed.info, produced by makeinfo version 4.13 from -../../doc//config.texi. +This is sed.info-t, produced by makeinfo version 6.3 from sed.texi. +This file documents version 4.3 of GNU 'sed', a stream editor. + + Copyright (C) 1998-2016 Free Software Foundation, Inc. + + Permission is granted to copy, distribute and/or modify this + document under the terms of the GNU Free Documentation License, + Version 1.3 or any later version published by the Free Software + Foundation; with no Invariant Sections, no Front-Cover Texts, and + no Back-Cover Texts. A copy of the license is included in the + section entitled "GNU Free Documentation License". INFO-DIR-SECTION Text creation and manipulation START-INFO-DIR-ENTRY * sed: (sed). Stream EDitor. END-INFO-DIR-ENTRY - This file documents version 4.2.2 of GNU `sed', a stream editor. - - Copyright (C) 1998, 1999, 2001, 2002, 2003, 2004 Free Software -Foundation, Inc. - - This document is released under the terms of the GNU Free -Documentation License as published by the Free Software Foundation; -either version 1.1, or (at your option) any later version. - - You should have received a copy of the GNU Free Documentation -License along with GNU `sed'; see the file `COPYING.DOC'. If not, -write to the Free Software Foundation, 59 Temple Place - Suite 330, -Boston, MA 02110-1301, USA. - - There are no Cover Texts and no Invariant Sections; this text, along -with its equivalent in the printed manual, constitutes the Title Page. - -File: sed.info, Node: Top, Next: Introduction, Up: (dir) - -sed, a stream editor -******************** - -This file documents version 4.2.2 of GNU `sed', a stream editor. +File: sed.info-t, Node: Top, Next: Introduction, Up: (dir) - Copyright (C) 1998, 1999, 2001, 2002, 2003, 2004 Free Software -Foundation, Inc. +GNU 'sed' +********* - This document is released under the terms of the GNU Free -Documentation License as published by the Free Software Foundation; -either version 1.1, or (at your option) any later version. +This file documents version 4.3 of GNU 'sed', a stream editor. - You should have received a copy of the GNU Free Documentation -License along with GNU `sed'; see the file `COPYING.DOC'. If not, -write to the Free Software Foundation, 59 Temple Place - Suite 330, -Boston, MA 02110-1301, USA. + Copyright (C) 1998-2016 Free Software Foundation, Inc. - There are no Cover Texts and no Invariant Sections; this text, along -with its equivalent in the printed manual, constitutes the Title Page. + Permission is granted to copy, distribute and/or modify this + document under the terms of the GNU Free Documentation License, + Version 1.3 or any later version published by the Free Software + Foundation; with no Invariant Sections, no Front-Cover Texts, and + no Back-Cover Texts. A copy of the license is included in the + section entitled "GNU Free Documentation License". * Menu: * Introduction:: Introduction * Invoking sed:: Invocation -* sed Programs:: `sed' programs +* sed scripts:: 'sed' scripts +* sed addresses:: Addresses: selecting lines +* sed regular expressions:: Regular expressions: selecting text +* advanced sed:: Advanced 'sed': cycles and buffers * Examples:: Some sample scripts -* Limitations:: Limitations and (non-)limitations of GNU `sed' -* Other Resources:: Other resources for learning about `sed' +* Limitations:: Limitations and (non-)limitations of GNU 'sed' +* Other Resources:: Other resources for learning about 'sed' * Reporting Bugs:: Reporting bugs - -* Extended regexps:: `egrep'-style regular expressions - +* GNU Free Documentation License:: Copying and sharing this manual * Concept Index:: A menu with all the topics in this manual. -* Command and Option Index:: A menu with all `sed' commands and +* Command and Option Index:: A menu with all 'sed' commands and command-line options. ---- The detailed node listing --- - -sed Programs: -* Execution Cycle:: How `sed' works -* Addresses:: Selecting lines with `sed' -* Regular Expressions:: Overview of regular expression syntax -* Common Commands:: Often used commands -* The "s" Command:: `sed''s Swiss Army Knife -* Other Commands:: Less frequently used commands -* Programming Commands:: Commands for `sed' gurus -* Extended Commands:: Commands specific of GNU `sed' -* Escapes:: Specifying special characters - -Examples: -* Centering lines:: -* Increment a number:: -* Rename files to lower case:: -* Print bash environment:: -* Reverse chars of lines:: -* tac:: Reverse lines of files -* cat -n:: Numbering lines -* cat -b:: Numbering non-blank lines -* wc -c:: Counting chars -* wc -w:: Counting words -* wc -l:: Counting lines -* head:: Printing the first lines -* tail:: Printing the last lines -* uniq:: Make duplicate lines unique -* uniq -d:: Print duplicated lines of input -* uniq -u:: Remove all duplicated lines -* cat -s:: Squeezing blank lines - -File: sed.info, Node: Introduction, Next: Invoking sed, Prev: Top, Up: Top +File: sed.info-t, Node: Introduction, Next: Invoking sed, Prev: Top, Up: Top 1 Introduction ************** -`sed' is a stream editor. A stream editor is used to perform basic text +'sed' is a stream editor. A stream editor is used to perform basic text transformations on an input stream (a file or input from a pipeline). While in some ways similar to an editor which permits scripted edits -(such as `ed'), `sed' works by making only one pass over the input(s), -and is consequently more efficient. But it is `sed''s ability to -filter text in a pipeline which particularly distinguishes it from -other types of editors. +(such as 'ed'), 'sed' works by making only one pass over the input(s), +and is consequently more efficient. But it is 'sed''s ability to filter +text in a pipeline which particularly distinguishes it from other types +of editors. -File: sed.info, Node: Invoking sed, Next: sed Programs, Prev: Introduction, Up: Top +File: sed.info-t, Node: Invoking sed, Next: sed scripts, Prev: Introduction, Up: Top -2 Invocation -************ +2 Running sed +************* -Normally `sed' is invoked like this: +This chapter covers how to run 'sed'. Details of 'sed' scripts and +individual 'sed' commands are discussed in the next chapter. + +* Menu: + +* Overview:: +* Command-Line Options:: +* Exit status:: + + +File: sed.info-t, Node: Overview, Next: Command-Line Options, Up: Invoking sed + +2.1 Overview +============ + +Normally 'sed' is invoked like this: sed SCRIPT INPUTFILE... - The full format for invoking `sed' is: + For example, to replace all occurrences of 'hello' to 'world' in the +file 'input.txt': - sed OPTIONS... [SCRIPT] [INPUTFILE...] + sed 's/hello/world/' input.txt > output.txt + + If you do not specify INPUTFILE, or if INPUTFILE is '-', 'sed' +filters the contents of the standard input. The following commands are +equivalent: + + sed 's/hello/world/' input.txt > output.txt + sed 's/hello/world/' < input.txt > output.txt + cat input.txt | sed 's/hello/world/' - > output.txt - If you do not specify INPUTFILE, or if INPUTFILE is `-', `sed' -filters the contents of the standard input. The SCRIPT is actually the -first non-option parameter, which `sed' specially considers a script -and not an input file if (and only if) none of the other OPTIONS -specifies a script to be executed, that is if neither of the `-e' and -`-f' options is specified. + 'sed' writes output to standard output. Use '-i' to edit files +in-place instead of printing to standard output. See also the 'W' and +'s///w' commands for writing output to other files. The following +command modifies 'file.txt' and does not produce any output: - `sed' may be invoked with the following command-line options: + sed -i 's/hello/world' file.txt -`--version' - Print out the version of `sed' that is being run and a copyright + By default 'sed' prints all processed input (except input that has +been modified/deleted by commands such as 'd'). Use '-n' to suppress +output, and the 'p' command to print specific lines. The following +command prints only line 45 of the input file: + + sed -n '45p' file.txt + + 'sed' treats multiple input files as one long stream. The following +example prints the first line of the first file ('one.txt') and the last +line of the last file ('three.txt'). Use '-s' to reverse this behavior. + + sed -n '1p ; $p' one.txt two.txt three.txt + + Without '-e' or '-f' options, 'sed' uses the first non-option +parameter as the SCRIPT, and the following non-option parameters as +input files. If '-e' or '-f' options are used to specify a SCRIPT, all +non-option parameters are taken as input files. Options '-e' and '-f' +can be combined, and can appear multiple times (in which case the final +effective SCRIPT will be concatenation of all the individual SCRIPTs). + + The following examples are equivalent: + + sed 's/hello/world/' input.txt > output.txt + + sed -e 's/hello/world/' input.txt > output.txt + sed --expression='s/hello/world/' input.txt > output.txt + + echo 's/hello/world/' > myscript.sed + sed -f myscript.sed input.txt > output.txt + sed --file=myscript.sed input.txt > output.txt + + +File: sed.info-t, Node: Command-Line Options, Next: Exit status, Prev: Overview, Up: Invoking sed + +2.2 Command-Line Options +======================== + +The full format for invoking 'sed' is: + + sed OPTIONS... [SCRIPT] [INPUTFILE...] + + 'sed' may be invoked with the following command-line options: + +'--version' + Print out the version of 'sed' that is being run and a copyright notice, then exit. -`--help' +'--help' Print a usage message briefly summarizing these command-line options and the bug-reporting address, then exit. -`-n' -`--quiet' -`--silent' - By default, `sed' prints out the pattern space at the end of each - cycle through the script (*note How `sed' works: Execution Cycle.). - These options disable this automatic printing, and `sed' only - produces output when explicitly told to via the `p' command. +'-n' +'--quiet' +'--silent' + By default, 'sed' prints out the pattern space at the end of each + cycle through the script (*note How 'sed' works: Execution Cycle.). + These options disable this automatic printing, and 'sed' only + produces output when explicitly told to via the 'p' command. -`-e SCRIPT' -`--expression=SCRIPT' +'-e SCRIPT' +'--expression=SCRIPT' Add the commands in SCRIPT to the set of commands to be run while processing the input. -`-f SCRIPT-FILE' -`--file=SCRIPT-FILE' +'-f SCRIPT-FILE' +'--file=SCRIPT-FILE' Add the commands contained in the file SCRIPT-FILE to the set of commands to be run while processing the input. -`-i[SUFFIX]' -`--in-place[=SUFFIX]' +'-i[SUFFIX]' +'--in-place[=SUFFIX]' This option specifies that files are to be edited in-place. GNU - `sed' does this by creating a temporary file and sending output to + 'sed' does this by creating a temporary file and sending output to this file rather than to the standard output.(1). - This option implies `-s'. + This option implies '-s'. When the end of the file is reached, the temporary file is renamed - to the output file's original name. The extension, if supplied, - is used to modify the name of the old file before renaming the + to the output file's original name. The extension, if supplied, is + used to modify the name of the old file before renaming the temporary file, thereby making a backup copy(2)). - This rule is followed: if the extension doesn't contain a `*', - then it is appended to the end of the current filename as a - suffix; if the extension does contain one or more `*' characters, - then _each_ asterisk is replaced with the current filename. This - allows you to add a prefix to the backup file, instead of (or in - addition to) a suffix, or even to place backup copies of the - original files into another directory (provided the directory - already exists). + This rule is followed: if the extension doesn't contain a '*', then + it is appended to the end of the current filename as a suffix; if + the extension does contain one or more '*' characters, then _each_ + asterisk is replaced with the current filename. This allows you to + add a prefix to the backup file, instead of (or in addition to) a + suffix, or even to place backup copies of the original files into + another directory (provided the directory already exists). If no extension is supplied, the original file is overwritten without making a backup. -`-l N' -`--line-length=N' - Specify the default line-wrap length for the `l' command. A - length of 0 (zero) means to never wrap long lines. If not - specified, it is taken to be 70. +'-l N' +'--line-length=N' + Specify the default line-wrap length for the 'l' command. A length + of 0 (zero) means to never wrap long lines. If not specified, it + is taken to be 70. -`--posix' - GNU `sed' includes several extensions to POSIX sed. In order to +'--posix' + GNU 'sed' includes several extensions to POSIX sed. In order to simplify writing portable scripts, this option disables all the extensions that this manual documents, including additional - commands. Most of the extensions accept `sed' programs that are - outside the syntax mandated by POSIX, but some of them (such as - the behavior of the `N' command described in *note Reporting - Bugs::) actually violate the standard. If you want to disable - only the latter kind of extension, you can set the - `POSIXLY_CORRECT' variable to a non-empty value. - -`-b' -`--binary' + commands. Most of the extensions accept 'sed' programs that are + outside the syntax mandated by POSIX, but some of them (such as the + behavior of the 'N' command described in *note Reporting Bugs::) + actually violate the standard. If you want to disable only the + latter kind of extension, you can set the 'POSIXLY_CORRECT' + variable to a non-empty value. + +'-b' +'--binary' This option is available on every platform, but is only effective where the operating system makes a distinction between text files and binary files. When such a distinction is made--as is the case for MS-DOS, Windows, Cygwin--text files are composed of lines separated by a carriage return _and_ a line feed character, and - `sed' does not see the ending CR. When this option is specified, - `sed' will open input files in binary mode, thus not requesting + 'sed' does not see the ending CR. When this option is specified, + 'sed' will open input files in binary mode, thus not requesting this special processing and considering lines to end at a line feed. -`--follow-symlinks' +'--follow-symlinks' This option is available only on platforms that support symbolic - links and has an effect only if option `-i' is specified. In this + links and has an effect only if option '-i' is specified. In this case, if the file that is specified on the command line is a - symbolic link, `sed' will follow the link and edit the ultimate + symbolic link, 'sed' will follow the link and edit the ultimate destination of the link. The default behavior is to break the symbolic link, so that the link destination will not be modified. -`-r' -`--regexp-extended' +'-E' +'-r' +'--regexp-extended' Use extended regular expressions rather than basic regular - expressions. Extended regexps are those that `egrep' accepts; - they can be clearer because they usually have less backslashes, - but are a GNU extension and hence scripts that use them are not - portable. *Note Extended regular expressions: Extended regexps. - -`-s' -`--separate' - By default, `sed' will consider the files specified on the command - line as a single continuous long stream. This GNU `sed' extension - allows the user to consider them as separate files: range - addresses (such as `/abc/,/def/') are not allowed to span several - files, line numbers are relative to the start of each file, `$' - refers to the last line of each file, and files invoked from the - `R' commands are rewound at the start of each file. - -`-u' -`--unbuffered' + expressions. Extended regexps are those that 'egrep' accepts; they + can be clearer because they usually have fewer backslashes. + Historically this was a GNU extension, but the '-E' extension has + since been added to the POSIX standard + (http://austingroupbugs.net/view.php?id=528), so use '-E' for + portability. GNU sed has accepted '-E' as an undocumented option + for years, and *BSD seds have accepted '-E' for years as well, but + scripts that use '-E' might not port to other older systems. *Note + Extended regular expressions: ERE syntax. + +'-s' +'--separate' + By default, 'sed' will consider the files specified on the command + line as a single continuous long stream. This GNU 'sed' extension + allows the user to consider them as separate files: range addresses + (such as '/abc/,/def/') are not allowed to span several files, line + numbers are relative to the start of each file, '$' refers to the + last line of each file, and files invoked from the 'R' commands are + rewound at the start of each file. + +'--sandbox' + In sandbox mode, 'e/w/r' commands are rejected - programs + containing them will be aborted without being run. Sandbox mode + ensures 'sed' operates only on the input files designated on the + command line, and cannot run external programs. + +'-u' +'--unbuffered' Buffer both input and output as minimally as practical. (This is - particularly useful if the input is coming from the likes of `tail + particularly useful if the input is coming from the likes of 'tail -f', and you wish to see the transformed output as soon as possible.) -`-z' -`--null-data' -`--zero-terminated' +'-z' +'--null-data' +'--zero-terminated' Treat the input as a set of lines, each terminated by a zero byte - (the ASCII `NUL' character) instead of a newline. This option can - be used with commands like `sort -z' and `find -print0' to process + (the ASCII 'NUL' character) instead of a newline. This option can + be used with commands like 'sort -z' and 'find -print0' to process arbitrary file names. - If no `-e', `-f', `--expression', or `--file' options are given on -the command-line, then the first non-option argument on the command -line is taken to be the SCRIPT to be executed. + If no '-e', '-f', '--expression', or '--file' options are given on +the command-line, then the first non-option argument on the command line +is taken to be the SCRIPT to be executed. If any command-line parameters remain after processing the above, these parameters are interpreted as the names of input files to be -processed. A file name of `-' refers to the standard input stream. -The standard input will be processed if no file names are specified. +processed. A file name of '-' refers to the standard input stream. The +standard input will be processed if no file names are specified. ---------- Footnotes ---------- - (1) This applies to commands such as `=', `a', `c', `i', `l', `p'. -You can still write to the standard output by using the `w' or `W' -commands together with the `/dev/stdout' special file + (1) This applies to commands such as '=', 'a', 'c', 'i', 'l', 'p'. +You can still write to the standard output by using the 'w' or 'W' +commands together with the '/dev/stdout' special file - (2) Note that GNU `sed' creates the backup file whether or not any + (2) Note that GNU 'sed' creates the backup file whether or not any output is actually changed. -File: sed.info, Node: sed Programs, Next: Examples, Prev: Invoking sed, Up: Top +File: sed.info-t, Node: Exit status, Prev: Command-Line Options, Up: Invoking sed -3 `sed' Programs -**************** +2.3 Exit status +=============== -A `sed' program consists of one or more `sed' commands, passed in by -one or more of the `-e', `-f', `--expression', and `--file' options, or -the first non-option argument if zero of these options are used. This -document will refer to "the" `sed' script; this is understood to mean -the in-order catenation of all of the SCRIPTs and SCRIPT-FILEs passed -in. +An exit status of zero indicates success, and a nonzero value indicates +failure. GNU 'sed' returns the following exit status error values: - Commands within a SCRIPT or SCRIPT-FILE can be separated by -semicolons (`;') or newlines (ASCII 10). Some commands, due to their -syntax, cannot be followed by semicolons working as command separators -and thus should be terminated with newlines or be placed at the end of -a SCRIPT or SCRIPT-FILE. Commands can also be preceded with optional -non-significant whitespace characters. - - Each `sed' command consists of an optional address or address range, -followed by a one-character command name and any additional -command-specific code. +0 + Successful completion. -* Menu: - -* Execution Cycle:: How `sed' works -* Addresses:: Selecting lines with `sed' -* Regular Expressions:: Overview of regular expression syntax -* Common Commands:: Often used commands -* The "s" Command:: `sed''s Swiss Army Knife -* Other Commands:: Less frequently used commands -* Programming Commands:: Commands for `sed' gurus -* Extended Commands:: Commands specific of GNU `sed' -* Escapes:: Specifying special characters +1 + Invalid command, invalid syntax, invalid regular expression or a + GNU 'sed' extension command used with '--posix'. - -File: sed.info, Node: Execution Cycle, Next: Addresses, Up: sed Programs +2 + One or more of the input file specified on the command line could + not be opened (e.g. if a file is not found, or read permission is + denied). Processing continued with other files. -3.1 How `sed' Works -=================== +4 + An I/O error, or a serious processing error during runtime, GNU + 'sed' aborted immediately. -`sed' maintains two data buffers: the active _pattern_ space, and the -auxiliary _hold_ space. Both are initially empty. + Additionally, the commands 'q' and 'Q' can be used to terminate 'sed' +with a custom exit code value (this is a GNU 'sed' extension): - `sed' operates by performing the following cycle on each line of -input: first, `sed' reads one line from the input stream, removes any -trailing newline, and places it in the pattern space. Then commands -are executed; each command can have an address associated to it: -addresses are a kind of condition code, and a command is only executed -if the condition is verified before the command is to be executed. + $ echo | sed 'Q42' ; echo $? + 42 - When the end of the script is reached, unless the `-n' option is in -use, the contents of pattern space are printed out to the output -stream, adding back the trailing newline if it was removed.(1) Then the -next cycle starts for the next input line. + +File: sed.info-t, Node: sed scripts, Next: sed addresses, Prev: Invoking sed, Up: Top - Unless special commands (like `D') are used, the pattern space is -deleted between two cycles. The hold space, on the other hand, keeps -its data between cycles (see commands `h', `H', `x', `g', `G' to move -data between both buffers). +3 'sed' scripts +*************** - ---------- Footnotes ---------- +* Menu: - (1) Actually, if `sed' prints a line without the terminating -newline, it will nevertheless print the missing newline as soon as more -text is sent to the same output stream, which gives the "least expected -surprise" even though it does not make commands like `sed -n p' exactly -identical to `cat'. +* sed script overview:: 'sed' script overview +* sed commands list:: 'sed' commands summary +* The "s" Command:: 'sed''s Swiss Army Knife +* Common Commands:: Often used commands +* Other Commands:: Less frequently used commands +* Programming Commands:: Commands for 'sed' gurus +* Extended Commands:: Commands specific of GNU 'sed' -File: sed.info, Node: Addresses, Next: Regular Expressions, Prev: Execution Cycle, Up: sed Programs +File: sed.info-t, Node: sed script overview, Next: sed commands list, Up: sed scripts -3.2 Selecting lines with `sed' -============================== +3.1 'sed' script overview +========================= -Addresses in a `sed' script can be in any of the following forms: -`NUMBER' - Specifying a line number will match only that line in the input. - (Note that `sed' counts lines continuously across all input files - unless `-i' or `-s' options are specified.) +A 'sed' program consists of one or more 'sed' commands, passed in by one +or more of the '-e', '-f', '--expression', and '--file' options, or the +first non-option argument if zero of these options are used. This +document will refer to "the" 'sed' script; this is understood to mean +the in-order concatenation of all of the SCRIPTs and SCRIPT-FILEs passed +in. *Note Overview::. -`FIRST~STEP' - This GNU extension matches every STEPth line starting with line - FIRST. In particular, lines will be selected when there exists a - non-negative N such that the current line-number equals FIRST + (N - * STEP). Thus, to select the odd-numbered lines, one would use - `1~2'; to pick every third line starting with the second, `2~3' - would be used; to pick every fifth line starting with the tenth, - use `10~5'; and `50~0' is just an obscure way of saying `50'. + 'sed' commands follow this syntax: -`$' - This address matches the last line of the last file of input, or - the last line of each file when the `-i' or `-s' options are - specified. + [addr]X[options] -`/REGEXP/' - This will select any line which matches the regular expression - REGEXP. If REGEXP itself includes any `/' characters, each must - be escaped by a backslash (`\'). + X is a single-letter 'sed' command. '[addr]' is an optional line +address. If '[addr]' is specified, the command X will be executed only +on the matched lines. '[addr]' can be a single line number, a regular +expression, or a range of lines (*note sed addresses::). Additional +'[options]' are used for some 'sed' commands. - The empty regular expression `//' repeats the last regular - expression match (the same holds if the empty regular expression is - passed to the `s' command). Note that modifiers to regular - expressions are evaluated when the regular expression is compiled, - thus it is invalid to specify them together with the empty regular - expression. + The following example deletes lines 30 to 35 in the input. '30,35' +is an address range. 'd' is the delete command: -`\%REGEXP%' - (The `%' may be replaced by any other single character.) + sed '30,35d' input.txt > output.txt - This also matches the regular expression REGEXP, but allows one to - use a different delimiter than `/'. This is particularly useful - if the REGEXP itself contains a lot of slashes, since it avoids - the tedious escaping of every `/'. If REGEXP itself includes any - delimiter characters, each must be escaped by a backslash (`\'). - -`/REGEXP/I' -`\%REGEXP%I' - The `I' modifier to regular-expression matching is a GNU extension - which causes the REGEXP to be matched in a case-insensitive manner. + The following example prints all input until a line starting with the +word 'foo' is found. If such line is found, 'sed' will terminate with +exit status 42. If such line was not found (and no other error +occurred), 'sed' will exit with status 0. '/^foo/' is a +regular-expression address. 'q' is the quit command. '42' is the +command option. -`/REGEXP/M' -`\%REGEXP%M' - The `M' modifier to regular-expression matching is a GNU `sed' - extension which directs GNU `sed' to match the regular expression - in `multi-line' mode. The modifier causes `^' and `$' to match - respectively (in addition to the normal behavior) the empty string - after a newline, and the empty string before a newline. There are - special character sequences (`\`' and `\'') which always match the - beginning or the end of the buffer. In addition, the period - character does not match a new-line character in multi-line mode. + sed '/^foo/q42' input.txt > output.txt + Commands within a SCRIPT or SCRIPT-FILE can be separated by +semicolons (';') or newlines (ASCII 10). Multiple scripts can be +specified with '-e' or '-f' options. - If no addresses are given, then all lines are matched; if one -address is given, then only lines matching that address are matched. + The following examples are all equivalent. They perform two 'sed' +operations: deleting any lines matching the regular expression '/^foo/', +and replacing all occurrences of the string 'hello' with 'world': - An address range can be specified by specifying two addresses -separated by a comma (`,'). An address range matches lines starting -from where the first address matches, and continues until the second -address matches (inclusively). + sed '/^foo/d ; s/hello/world/' input.txt > output.txt - If the second address is a REGEXP, then checking for the ending -match will start with the line _following_ the line which matched the -first address: a range will always span at least two lines (except of -course if the input stream ends). + sed -e '/^foo/d' -e 's/hello/world/' input.txt > output.txt - If the second address is a NUMBER less than (or equal to) the line -matching the first address, then only the one line is matched. - - GNU `sed' also supports some special two-address forms; all these -are GNU extensions: -`0,/REGEXP/' - A line number of `0' can be used in an address specification like - `0,/REGEXP/' so that `sed' will try to match REGEXP in the first - input line too. In other words, `0,/REGEXP/' is similar to - `1,/REGEXP/', except that if ADDR2 matches the very first line of - input the `0,/REGEXP/' form will consider it to end the range, - whereas the `1,/REGEXP/' form will match the beginning of its - range and hence make the range span up to the _second_ occurrence - of the regular expression. - - Note that this is the only place where the `0' address makes - sense; there is no 0-th line and commands which are given the `0' - address in any other way will give an error. - -`ADDR1,+N' - Matches ADDR1 and the N lines following ADDR1. + echo '/^foo/d' > script.sed + echo 's/hello/world/' >> script.sed + sed -f script.sed input.txt > output.txt -`ADDR1,~N' - Matches ADDR1 and the lines following ADDR1 until the next line - whose input line number is a multiple of N. + echo 's/hello/world/' > script2.sed + sed -e '/^foo/d' -f script2.sed input.txt > output.txt - Appending the `!' character to the end of an address specification -negates the sense of the match. That is, if the `!' character follows -an address range, then only lines which do _not_ match the address range -will be selected. This also works for singleton addresses, and, -perhaps perversely, for the null address. + Commands 'a', 'c', 'i', due to their syntax, cannot be followed by +semicolons working as command separators and thus should be terminated +with newlines or be placed at the end of a SCRIPT or SCRIPT-FILE. +Commands can also be preceded with optional non-significant whitespace +characters. -File: sed.info, Node: Regular Expressions, Next: Common Commands, Prev: Addresses, Up: sed Programs +File: sed.info-t, Node: sed commands list, Next: The "s" Command, Prev: sed script overview, Up: sed scripts -3.3 Overview of Regular Expression Syntax -========================================= +3.2 'sed' commands summary +========================== -To know how to use `sed', people should understand regular expressions -("regexp" for short). A regular expression is a pattern that is -matched against a subject string from left to right. Most characters -are "ordinary": they stand for themselves in a pattern, and match the -corresponding characters in the subject. As a trivial example, the -pattern +The following commands are supported in GNU 'sed'. Some are standard +POSIX commands, while other are GNU extensions. Details and examples +for each command are in the following sections. (Mnemonics) are shown +in parentheses. - The quick brown fox +'a\' +'TEXT' + Append TEXT after a line. -matches a portion of a subject string that is identical to itself. The -power of regular expressions comes from the ability to include -alternatives and repetitions in the pattern. These are encoded in the -pattern by the use of "special characters", which do not stand for -themselves but instead are interpreted in some special way. Here is a -brief description of regular expression syntax as used in `sed'. +'a TEXT' + Append TEXT after a line (alternative syntax). -`CHAR' - A single ordinary character matches itself. +'b LABEL' + Branch unconditionally to LABEL. The LABEL may be omitted, in + which case the next cycle is started. -`*' - Matches a sequence of zero or more instances of matches for the - preceding regular expression, which must be an ordinary character, - a special character preceded by `\', a `.', a grouped regexp (see - below), or a bracket expression. As a GNU extension, a postfixed - regular expression can also be followed by `*'; for example, `a**' - is equivalent to `a*'. POSIX 1003.1-2001 says that `*' stands for - itself when it appears at the start of a regular expression or - subexpression, but many nonGNU implementations do not support this - and portable scripts should instead use `\*' in these contexts. +'c\' +'TEXT' + Replace (change) lines with TEXT. -`\+' - As `*', but matches one or more. It is a GNU extension. +'c TEXT' + Replace (change) lines with TEXT (alternative syntax). -`\?' - As `*', but only matches zero or one. It is a GNU extension. +'d' + Delete the pattern space; immediately start next cycle. -`\{I\}' - As `*', but matches exactly I sequences (I is a decimal integer; - for portability, keep it between 0 and 255 inclusive). +'D' + If pattern space contains newlines, delete text in the pattern + space up to the first newline, and restart cycle with the resultant + pattern space, without reading a new line of input. -`\{I,J\}' - Matches between I and J, inclusive, sequences. + If pattern space contains no newline, start a normal new cycle as + if the 'd' command was issued. -`\{I,\}' - Matches more than or equal to I sequences. +'e' + Executes the command that is found in pattern space and replaces + the pattern space with the output; a trailing newline is + suppressed. -`\(REGEXP\)' - Groups the inner REGEXP as a whole, this is used to: +'e COMMAND' + Executes COMMAND and sends its output to the output stream. The + command can run across multiple lines, all but the last ending with + a back-slash. - * Apply postfix operators, like `\(abcd\)*': this will search - for zero or more whole sequences of `abcd', while `abcd*' - would search for `abc' followed by zero or more occurrences - of `d'. Note that support for `\(abcd\)*' is required by - POSIX 1003.1-2001, but many non-GNU implementations do not - support it and hence it is not universally portable. +'F' + (filename) Print the file name of the current input file (with a + trailing newline). - * Use back references (see below). +'g' + Replace the contents of the pattern space with the contents of the + hold space. -`.' - Matches any character, including newline. +'G' + Append a newline to the contents of the pattern space, and then + append the contents of the hold space to that of the pattern space. -`^' - Matches the null string at beginning of the pattern space, i.e. - what appears after the circumflex must appear at the beginning of +'h' + (hold) Replace the contents of the hold space with the contents of the pattern space. - In most scripts, pattern space is initialized to the content of - each line (*note How `sed' works: Execution Cycle.). So, it is a - useful simplification to think of `^#include' as matching only - lines where `#include' is the first thing on line--if there are - spaces before, for example, the match fails. This simplification - is valid as long as the original content of pattern space is not - modified, for example with an `s' command. - - `^' acts as a special character only at the beginning of the - regular expression or subexpression (that is, after `\(' or `\|'). - Portable scripts should avoid `^' at the beginning of a - subexpression, though, as POSIX allows implementations that treat - `^' as an ordinary character in that context. - -`$' - It is the same as `^', but refers to end of pattern space. `$' - also acts as a special character only at the end of the regular - expression or subexpression (that is, before `\)' or `\|'), and - its use at the end of a subexpression is not portable. - -`[LIST]' -`[^LIST]' - Matches any single character in LIST: for example, `[aeiou]' - matches all vowels. A list may include sequences like - `CHAR1-CHAR2', which matches any character between (inclusive) - CHAR1 and CHAR2. - - A leading `^' reverses the meaning of LIST, so that it matches any - single character _not_ in LIST. To include `]' in the list, make - it the first character (after the `^' if needed), to include `-' - in the list, make it the first or last; to include `^' put it - after the first character. - - The characters `$', `*', `.', `[', and `\' are normally not - special within LIST. For example, `[\*]' matches either `\' or - `*', because the `\' is not special here. However, strings like - `[.ch.]', `[=a=]', and `[:space:]' are special within LIST and - represent collating symbols, equivalence classes, and character - classes, respectively, and `[' is therefore special within LIST - when it is followed by `.', `=', or `:'. Also, when not in - `POSIXLY_CORRECT' mode, special escapes like `\n' and `\t' are - recognized within LIST. *Note Escapes::. - -`REGEXP1\|REGEXP2' - Matches either REGEXP1 or REGEXP2. Use parentheses to use complex - alternative regular expressions. The matching process tries each - alternative in turn, from left to right, and the first one that - succeeds is used. It is a GNU extension. - -`REGEXP1REGEXP2' - Matches the concatenation of REGEXP1 and REGEXP2. Concatenation - binds more tightly than `\|', `^', and `$', but less tightly than - the other regular expression operators. - -`\DIGIT' - Matches the DIGIT-th `\(...\)' parenthesized subexpression in the - regular expression. This is called a "back reference". - Subexpressions are implicity numbered by counting occurrences of - `\(' left-to-right. - -`\n' - Matches the newline character. - -`\CHAR' - Matches CHAR, where CHAR is one of `$', `*', `.', `[', `\', or `^'. - Note that the only C-like backslash sequences that you can - portably assume to be interpreted are `\n' and `\\'; in particular - `\t' is not portable, and matches a `t' under most implementations - of `sed', rather than a tab character. - - - Note that the regular expression matcher is greedy, i.e., matches -are attempted from left to right and, if two or more matches are -possible starting at the same character, it selects the longest. - -Examples: -`abcdef' - Matches `abcdef'. - -`a*b' - Matches zero or more `a's followed by a single `b'. For example, - `b' or `aaaaab'. +'H' + Append a newline to the contents of the hold space, and then append + the contents of the pattern space to that of the hold space. -`a\?b' - Matches `b' or `ab'. +'i\' +'TEXT' + insert TEXT before a line. -`a\+b\+' - Matches one or more `a's followed by one or more `b's: `ab' is the - shortest possible match, but other examples are `aaaab' or - `abbbbb' or `aaaaaabbbbbbb'. +'i TEXT' + insert TEXT before a line (alternative syntax). -`.*' -`.\+' - These two both match all the characters in a string; however, the - first matches every string (including the empty string), while the - second matches only strings containing at least one character. - -`^main.*(.*)' - This matches a string starting with `main', followed by an opening - and closing parenthesis. The `n', `(' and `)' need not be - adjacent. - -`^#' - This matches a string beginning with `#'. +'l' + Print the pattern space in an unambiguous form. -`\\$' - This matches a string ending with a single backslash. The regexp - contains two backslashes for escaping. - -`\$' - Instead, this matches a string consisting of a single dollar sign, - because it is escaped. +'n' + (next) If auto-print is not disabled, print the pattern space, + then, regardless, replace the pattern space with the next line of + input. If there is no more input then 'sed' exits without + processing any more commands. -`[a-zA-Z0-9]' - In the C locale, this matches any ASCII letters or digits. - -`[^ tab]\+' - (Here `tab' stands for a single tab character.) This matches a - string of one or more characters, none of which is a space or a - tab. Usually this means a word. +'N' + Add a newline to the pattern space, then append the next line of + input to the pattern space. If there is no more input then 'sed' + exits without processing any more commands. -`^\(.*\)\n\1$' - This matches a string consisting of two equal substrings separated - by a newline. +'p' + Print the pattern space. -`.\{9\}A$' - This matches nine characters followed by an `A'. +'P' + Print the pattern space, up to the first <newline>. -`^.\{15\}A' - This matches the start of a string that contains 16 characters, - the last of which is an `A'. +'q[EXIT-CODE]' + (quit) Exit 'sed' without processing any more commands or input. +'Q[EXIT-CODE]' + (quit) This command is the same as 'q', but will not print the + contents of pattern space. Like 'q', it provides the ability to + return an exit code to the caller. - -File: sed.info, Node: Common Commands, Next: The "s" Command, Prev: Regular Expressions, Up: sed Programs +'r filename' + Reads text file a file. Example: -3.4 Often-Used Commands -======================= - -If you use `sed' at all, you will quite likely want to know these -commands. +'R filename' + Queue a line of FILENAME to be read and inserted into the output + stream at the end of the current cycle, or when the next input line + is read. + +'s/REGEXP/REPLACEMENT/[FLAGS]' + (substitute) Match the regular-expression against the content of + the pattern space. If found, replace matched string with + REPLACEMENT. + +'t LABEL' + (test) Branch to LABEL only if there has been a successful + 's'ubstitution since the last input line was read or conditional + branch was taken. The LABEL may be omitted, in which case the next + cycle is started. -`#' - [No addresses allowed.] +'T LABEL' + (test) Branch to LABEL only if there have been no successful + 's'ubstitutions since the last input line was read or conditional + branch was taken. The LABEL may be omitted, in which case the next + cycle is started. - The `#' character begins a comment; the comment continues until - the next newline. +'v [VERSION]' + (version) This command does nothing, but makes 'sed' fail if GNU + 'sed' extensions are not supported, or if the requested version is + not available. - If you are concerned about portability, be aware that some - implementations of `sed' (which are not POSIX conformant) may only - support a single one-line comment, and then only when the very - first character of the script is a `#'. +'w filename' + Write the pattern space to FILENAME. - Warning: if the first two characters of the `sed' script are `#n', - then the `-n' (no-autoprint) option is forced. If you want to put - a comment in the first line of your script and that comment begins - with the letter `n' and you do not want this behavior, then be - sure to either use a capital `N', or place at least one space - before the `n'. +'W filename' + Write to the given filename the portion of the pattern space up to + the first newline -`q [EXIT-CODE]' - This command only accepts a single address. +'x' + Exchange the contents of the hold and pattern spaces. - Exit `sed' without processing any more commands or input. Note - that the current pattern space is printed if auto-print is not - disabled with the `-n' options. The ability to return an exit - code from the `sed' script is a GNU `sed' extension. +'y/src/dst/' + Transliterate any characters in the pattern space which match any + of the SOURCE-CHARS with the corresponding character in DEST-CHARS. -`d' - Delete the pattern space; immediately start next cycle. +'z' + (zap) This command empties the content of pattern space. -`p' - Print out the pattern space (to the standard output). This - command is usually only used in conjunction with the `-n' - command-line option. +'#' + A comment, until the next newline. -`n' - If auto-print is not disabled, print the pattern space, then, - regardless, replace the pattern space with the next line of input. - If there is no more input then `sed' exits without processing any - more commands. +'{ CMD ; CMD ... }' + Group several commands together. -`{ COMMANDS }' - A group of commands may be enclosed between `{' and `}' characters. - This is particularly useful when you want a group of commands to - be triggered by a single address (or address-range) match. +'=' + Print the current input line number (with a trailing newline). +': LABEL' + Specify the location of LABEL for branch commands ('b', 't', 'T'). -File: sed.info, Node: The "s" Command, Next: Other Commands, Prev: Common Commands, Up: sed Programs +File: sed.info-t, Node: The "s" Command, Next: Common Commands, Prev: sed commands list, Up: sed scripts -3.5 The `s' Command +3.3 The 's' Command =================== -The syntax of the `s' (as in substitute) command is -`s/REGEXP/REPLACEMENT/FLAGS'. The `/' characters may be uniformly -replaced by any other single character within any given `s' command. -The `/' character (or whatever other character is used in its stead) -can appear in the REGEXP or REPLACEMENT only if it is preceded by a `\' -character. +The 's' command (as in substitute) is probably the most important in +'sed' and has a lot of different options. The syntax of the 's' command +is 's/REGEXP/REPLACEMENT/FLAGS'. - The `s' command is probably the most important in `sed' and has a -lot of different options. Its basic concept is simple: the `s' command -attempts to match the pattern space against the supplied REGEXP; if the + Its basic concept is simple: the 's' command attempts to match the +pattern space against the supplied regular expression REGEXP; if the match is successful, then that portion of the pattern space which was matched is replaced with REPLACEMENT. - The REPLACEMENT can contain `\N' (N being a number from 1 to 9, + For details about REGEXP syntax *note Regular Expression Addresses: +Regexp Addresses. + + The REPLACEMENT can contain '\N' (N being a number from 1 to 9, inclusive) references, which refer to the portion of the match which is -contained between the Nth `\(' and its matching `\)'. Also, the -REPLACEMENT can contain unescaped `&' characters which reference the -whole matched portion of the pattern space. Finally, as a GNU `sed' -extension, you can include a special sequence made of a backslash and -one of the letters `L', `l', `U', `u', or `E'. The meaning is as -follows: +contained between the Nth '\(' and its matching '\)'. Also, the +REPLACEMENT can contain unescaped '&' characters which reference the +whole matched portion of the pattern space. -`\L' - Turn the replacement to lowercase until a `\U' or `\E' is found, + The '/' characters may be uniformly replaced by any other single +character within any given 's' command. The '/' character (or whatever +other character is used in its stead) can appear in the REGEXP or +REPLACEMENT only if it is preceded by a '\' character. -`\l' + Finally, as a GNU 'sed' extension, you can include a special sequence +made of a backslash and one of the letters 'L', 'l', 'U', 'u', or 'E'. +The meaning is as follows: + +'\L' + Turn the replacement to lowercase until a '\U' or '\E' is found, + +'\l' Turn the next character to lowercase, -`\U' - Turn the replacement to uppercase until a `\L' or `\E' is found, +'\U' + Turn the replacement to uppercase until a '\L' or '\E' is found, -`\u' +'\u' Turn the next character to uppercase, -`\E' - Stop case conversion started by `\L' or `\U'. +'\E' + Stop case conversion started by '\L' or '\U'. - When the `g' flag is being used, case conversion does not propagate + When the 'g' flag is being used, case conversion does not propagate from one occurrence of the regular expression to another. For example, -when the following command is executed with `a-b-' in pattern space: +when the following command is executed with 'a-b-' in pattern space: s/\(b\?\)-/x\u\1/g -the output is `axxB'. When replacing the first `-', the `\u' sequence -only affects the empty replacement of `\1'. It does not affect the `x' -character that is added to pattern space when replacing `b-' with `xB'. +the output is 'axxB'. When replacing the first '-', the '\u' sequence +only affects the empty replacement of '\1'. It does not affect the 'x' +character that is added to pattern space when replacing 'b-' with 'xB'. - On the other hand, `\l' and `\u' do affect the remainder of the + On the other hand, '\l' and '\u' do affect the remainder of the replacement text if they are followed by an empty substitution. With -`a-b-' in pattern space, the following command: +'a-b-' in pattern space, the following command: s/\(b\?\)-/\u\1x/g -will replace `-' with `X' (uppercase) and `b-' with `Bx'. If this -behavior is undesirable, you can prevent it by adding a `\E' -sequence--after `\1' in this case. +will replace '-' with 'X' (uppercase) and 'b-' with 'Bx'. If this +behavior is undesirable, you can prevent it by adding a '\E' +sequence--after '\1' in this case. - To include a literal `\', `&', or newline in the final replacement, -be sure to precede the desired `\', `&', or newline in the REPLACEMENT -with a `\'. + To include a literal '\', '&', or newline in the final replacement, +be sure to precede the desired '\', '&', or newline in the REPLACEMENT +with a '\'. - The `s' command can be followed by zero or more of the following + The 's' command can be followed by zero or more of the following FLAGS: -`g' +'g' Apply the replacement to _all_ matches to the REGEXP, not just the first. -`NUMBER' +'NUMBER' Only replace the NUMBERth match of the REGEXP. - Note: the POSIX standard does not specify what should happen when - you mix the `g' and NUMBER modifiers, and currently there is no - widely agreed upon meaning across `sed' implementations. For GNU - `sed', the interaction is defined to be: ignore matches before the - NUMBERth, and then match and replace all matches from the NUMBERth - on. + interaction in 's' command Note: the POSIX standard does not + specify what should happen when you mix the 'g' and NUMBER + modifiers, and currently there is no widely agreed upon meaning + across 'sed' implementations. For GNU 'sed', the interaction is + defined to be: ignore matches before the NUMBERth, and then match + and replace all matches from the NUMBERth on. -`p' +'p' If the substitution was made, then print the new pattern space. - Note: when both the `p' and `e' options are specified, the - relative ordering of the two produces very different results. In - general, `ep' (evaluate then print) is what you want, but - operating the other way round can be useful for debugging. For - this reason, the current version of GNU `sed' interprets specially - the presence of `p' options both before and after `e', printing - the pattern space before and after evaluation, while in general - flags for the `s' command show their effect just once. This - behavior, although documented, might change in future versions. - -`w FILE-NAME' + Note: when both the 'p' and 'e' options are specified, the relative + ordering of the two produces very different results. In general, + 'ep' (evaluate then print) is what you want, but operating the + other way round can be useful for debugging. For this reason, the + current version of GNU 'sed' interprets specially the presence of + 'p' options both before and after 'e', printing the pattern space + before and after evaluation, while in general flags for the 's' + command show their effect just once. This behavior, although + documented, might change in future versions. + +'w FILE-NAME' If the substitution was made, then write out the result to the - named file. As a GNU `sed' extension, two special values of - FILE-NAME are supported: `/dev/stderr', which writes the result to - the standard error, and `/dev/stdout', which writes to the standard + named file. As a GNU 'sed' extension, two special values of + FILE-NAME are supported: '/dev/stderr', which writes the result to + the standard error, and '/dev/stdout', which writes to the standard output.(1) -`e' +'e' This command allows one to pipe input from a shell command into pattern space. If a substitution was made, the command that is found in pattern space is executed and pattern space is replaced with its output. A trailing newline is suppressed; results are undefined if the command to be executed contains a NUL character. - This is a GNU `sed' extension. - -`I' -`i' - The `I' modifier to regular-expression matching is a GNU extension - which makes `sed' match REGEXP in a case-insensitive manner. - -`M' -`m' - The `M' modifier to regular-expression matching is a GNU `sed' - extension which directs GNU `sed' to match the regular expression - in `multi-line' mode. The modifier causes `^' and `$' to match + This is a GNU 'sed' extension. + +'I' +'i' + The 'I' modifier to regular-expression matching is a GNU extension + which makes 'sed' match REGEXP in a case-insensitive manner. + +'M' +'m' + The 'M' modifier to regular-expression matching is a GNU 'sed' + extension which directs GNU 'sed' to match the regular expression + in 'multi-line' mode. The modifier causes '^' and '$' to match respectively (in addition to the normal behavior) the empty string after a newline, and the empty string before a newline. There are - special character sequences (`\`' and `\'') which always match the + special character sequences ('\`' and '\'') which always match the beginning or the end of the buffer. In addition, the period character does not match a new-line character in multi-line mode. - ---------- Footnotes ---------- - (1) This is equivalent to `p' unless the `-i' option is being used. + (1) This is equivalent to 'p' unless the '-i' option is being used. + + +File: sed.info-t, Node: Common Commands, Next: Other Commands, Prev: The "s" Command, Up: sed scripts + +3.4 Often-Used Commands +======================= + +If you use 'sed' at all, you will quite likely want to know these +commands. + +'#' + [No addresses allowed.] + + The '#' character begins a comment; the comment continues until the + next newline. + + If you are concerned about portability, be aware that some + implementations of 'sed' (which are not POSIX conforming) may only + support a single one-line comment, and then only when the very + first character of the script is a '#'. + + Warning: if the first two characters of the 'sed' script are '#n', + then the '-n' (no-autoprint) option is forced. If you want to put + a comment in the first line of your script and that comment begins + with the letter 'n' and you do not want this behavior, then be sure + to either use a capital 'N', or place at least one space before the + 'n'. + +'q [EXIT-CODE]' + Exit 'sed' without processing any more commands or input. + + Example: stop after printing the second line: + $ seq 3 | sed 2q + 1 + 2 + + This command only accepts a single address. Note that the current + pattern space is printed if auto-print is not disabled with the + '-n' options. The ability to return an exit code from the 'sed' + script is a GNU 'sed' extension. + + See also the GNU 'sed' extension 'Q' command which quits silently + without printing the current pattern space. + +'d' + Delete the pattern space; immediately start next cycle. + + Example: delete the second input line: + $ seq 3 | sed 2d + 1 + 3 + +'p' + Print out the pattern space (to the standard output). This command + is usually only used in conjunction with the '-n' command-line + option. + + Example: print only the second input line: + $ seq 3 | sed -n 2p + 2 + +'n' + If auto-print is not disabled, print the pattern space, then, + regardless, replace the pattern space with the next line of input. + If there is no more input then 'sed' exits without processing any + more commands. + + This command is useful to skip lines (e.g. process every Nth + line). + + Example: perform substitution on every 3rd line (i.e. two 'n' + commands skip two lines): + $ seq 6 | sed 'n;n;s/./x/' + 1 + 2 + x + 4 + 5 + x + + GNU 'sed' provides an extension address syntax of FIRST~STEP to + achieve the same result: + + $ seq 6 | sed '0~3s/./x/' + 1 + 2 + x + 4 + 5 + x + +'{ COMMANDS }' + A group of commands may be enclosed between '{' and '}' characters. + This is particularly useful when you want a group of commands to be + triggered by a single address (or address-range) match. + + Example: perform substitution then print the second input line: + $ seq 3 | sed -n '2{s/2/X/ ; p}' + X -File: sed.info, Node: Other Commands, Next: Programming Commands, Prev: The "s" Command, Up: sed Programs +File: sed.info-t, Node: Other Commands, Next: Programming Commands, Prev: Common Commands, Up: sed scripts -3.6 Less Frequently-Used Commands +3.5 Less Frequently-Used Commands ================================= Though perhaps less frequently used than those in the previous section, -some very small yet useful `sed' scripts can be built with these +some very small yet useful 'sed' scripts can be built with these commands. -`y/SOURCE-CHARS/DEST-CHARS/' - (The `/' characters may be uniformly replaced by any other single - character within any given `y' command.) - +'y/SOURCE-CHARS/DEST-CHARS/' Transliterate any characters in the pattern space which match any of the SOURCE-CHARS with the corresponding character in DEST-CHARS. - Instances of the `/' (or whatever other character is used in its - stead), `\', or newlines can appear in the SOURCE-CHARS or - DEST-CHARS lists, provide that each instance is escaped by a `\'. + Example: transliterate 'a-j' into '0-9': + $ echo hello world | sed 'y/abcdefghij/0123456789/' + 74llo worl3 + + (The '/' characters may be uniformly replaced by any other single + character within any given 'y' command.) + + Instances of the '/' (or whatever other character is used in its + stead), '\', or newlines can appear in the SOURCE-CHARS or + DEST-CHARS lists, provide that each instance is escaped by a '\'. The SOURCE-CHARS and DEST-CHARS lists _must_ contain the same number of characters (after de-escaping). -`a\' -`TEXT' - As a GNU extension, this command accepts two addresses. + See the 'tr' command from GNU coreutils for similar functionality. - Queue the lines of text which follow this command (each but the - last ending with a `\', which are removed from the output) to be - output at the end of the current cycle, or when the next input - line is read. +'a TEXT' + Appending TEXT after a line. This is a GNU extension to the + standard 'a' command - see below for details. - Escape sequences in TEXT are processed, so you should use `\\' in - TEXT to print a single backslash. + Example: Add the word 'hello' after the second line: + $ seq 3 | sed '2a hello' + 1 + 2 + hello + 3 - As a GNU extension, if between the `a' and the newline there is - other than a whitespace-`\' sequence, then the text of this line, - starting at the first non-whitespace character after the `a', is - taken as the first line of the TEXT block. (This enables a - simplification in scripting a one-line add.) This extension also - works with the `i' and `c' commands. + Leading whitespaces after the 'a' command are ignored. The text to + add is read until the end of the line. + +'a\' +'TEXT' + Appending TEXT after a line. + + Example: Add 'hello' after the second line (-| indicates printed + output lines): + $ seq 3 | sed '2a\ + hello' + -|1 + -|2 + -|hello + -|3 + + The 'a' command queues the lines of text which follow this command + (each but the last ending with a '\', which are removed from the + output) to be output at the end of the current cycle, or when the + next input line is read. -`i\' -`TEXT' As a GNU extension, this command accepts two addresses. - Immediately output the lines of text which follow this command - (each but the last ending with a `\', which are removed from the - output). + Escape sequences in TEXT are processed, so you should use '\\' in + TEXT to print a single backslash. -`c\' -`TEXT' - Delete the lines matching the address or address-range, and output - the lines of text which follow this command (each but the last - ending with a `\', which are removed from the output) in place of - the last line (or in place of each line, if no addresses were - specified). A new cycle is started after this command is done, - since the pattern space will have been deleted. + The commands resume after the last line without a backslash ('\') - + 'world' in the following example: + $ seq 3 | sed '2a\ + hello\ + world + 3s/./X/' + -|1 + -|2 + -|hello + -|world + -|X + + As a GNU extension, the 'a' command and TEXT can be separated into + two '-e' parameters, enabling easier scripting: + $ seq 3 | sed -e '2a\' -e hello + 1 + 2 + hello + 3 + + $ sed -e '2a\' -e "$VAR" + +'i TEXT' + insert TEXT before a line. This is a GNU extension to the standard + 'i' command - see below for details. + + Example: Insert the word 'hello' before the second line: + $ seq 3 | sed '2i hello' + 1 + hello + 2 + 3 + + Leading whitespaces after the 'i' command are ignored. The text to + add is read until the end of the line. + +'i\' +'TEXT' + Immediately output the lines of text which follow this command. + + Example: Insert 'hello' before the second line (-| indicates + printed output lines): + $ seq 3 | sed '2i\ + hello' + -|1 + -|hello + -|2 + -|3 -`=' As a GNU extension, this command accepts two addresses. + Escape sequences in TEXT are processed, so you should use '\\' in + TEXT to print a single backslash. + + The commands resume after the last line without a backslash ('\') - + 'world' in the following example: + $ seq 3 | sed '2i\ + hello\ + world + s/./X/' + -|X + -|hello + -|world + -|X + -|X + + As a GNU extension, the 'i' command and TEXT can be separated into + two '-e' parameters, enabling easier scripting: + $ seq 3 | sed -e '2i\' -e hello + 1 + hello + 2 + 3 + + $ sed -e '2i\' -e "$VAR" + +'c TEXT' + Replaces the line(s) with TEXT. This is a GNU extension to the + standard 'c' command - see below for details. + + Example: Replace the 2nd to 9th lines with the word 'hello': + $ seq 10 | sed '2,9c hello' + 1 + hello + 10 + + Leading whitespaces after the 'c' command are ignored. The text to + add is read until the end of the line. + +'c\' +'TEXT' + Delete the lines matching the address or address-range, and output + the lines of text which follow this command. + + Example: Replace 2nd to 4th lines with the words 'hello' and + 'world' (-| indicates printed output lines): + $ seq 5 | sed '2,4c\ + hello\ + world' + -|1 + -|hello + -|world + -|5 + + If no addresses are given, each line is replaced. + + A new cycle is started after this command is done, since the + pattern space will have been deleted. In the following example, + the 'c' starts a new cycle and the substitution command is not + performed on the replaced text: + + $ seq 3 | sed '2c\ + hello + s/./X/' + -|X + -|hello + -|X + + As a GNU extension, the 'c' command and TEXT can be separated into + two '-e' parameters, enabling easier scripting: + $ seq 3 | sed -e '2c\' -e hello + 1 + hello + 3 + + $ sed -e '2c\' -e "$VAR" + +'=' Print out the current input line number (with a trailing newline). -`l N' + $ printf '%s\n' aaa bbb ccc | sed = + 1 + aaa + 2 + bbb + 3 + ccc + + As a GNU extension, this command accepts two addresses. + +'l N' Print the pattern space in an unambiguous form: non-printable - characters (and the `\' character) are printed in C-style escaped - form; long lines are split, with a trailing `\' character to - indicate the split; the end of each line is marked with a `$'. + characters (and the '\' character) are printed in C-style escaped + form; long lines are split, with a trailing '\' character to + indicate the split; the end of each line is marked with a '$'. N specifies the desired line-wrap length; a length of 0 (zero) means to never wrap long lines. If omitted, the default as specified on the command line is used. The N parameter is a GNU - `sed' extension. + 'sed' extension. -`r FILENAME' - As a GNU extension, this command accepts two addresses. +'r FILENAME' + + Reads text file a file. Example: + + $ seq 3 | sed '2r/etc/hostname' + 1 + 2 + fencepost.gnu.org + 3 Queue the contents of FILENAME to be read and inserted into the output stream at the end of the current cycle, or when the next input line is read. Note that if FILENAME cannot be read, it is treated as if it were an empty file, without any error indication. - As a GNU `sed' extension, the special value `/dev/stdin' is + As a GNU 'sed' extension, the special value '/dev/stdin' is supported for the file name, which reads the contents of the standard input. -`w FILENAME' - Write the pattern space to FILENAME. As a GNU `sed' extension, - two special values of FILE-NAME are supported: `/dev/stderr', - which writes the result to the standard error, and `/dev/stdout', - which writes to the standard output.(1) + As a GNU extension, this command accepts two addresses. The file + will then be reread and inserted on each of the addressed lines. - The file will be created (or truncated) before the first input - line is read; all `w' commands (including instances of the `w' flag - on successful `s' commands) which refer to the same FILENAME are +'w FILENAME' + Write the pattern space to FILENAME. As a GNU 'sed' extension, two + special values of FILE-NAME are supported: '/dev/stderr', which + writes the result to the standard error, and '/dev/stdout', which + writes to the standard output.(1) + + The file will be created (or truncated) before the first input line + is read; all 'w' commands (including instances of the 'w' flag on + successful 's' commands) which refer to the same FILENAME are output without closing and reopening the file. -`D' +'D' If pattern space contains no newline, start a normal new cycle as - if the `d' command was issued. Otherwise, delete text in the + if the 'd' command was issued. Otherwise, delete text in the pattern space up to the first newline, and restart cycle with the resultant pattern space, without reading a new line of input. -`N' +'N' Add a newline to the pattern space, then append the next line of - input to the pattern space. If there is no more input then `sed' + input to the pattern space. If there is no more input then 'sed' exits without processing any more commands. -`P' + When '-z' is used, a zero byte (the ascii 'NUL' character) is added + between the lines (instead of a new line). + + By default 'sed' does not terminate if there is no 'next' input + line. This is a GNU extension which can be disabled with + '--posix'. *Note N command on the last line: N_command_last_line. + +'P' Print out the portion of the pattern space up to the first newline. -`h' +'h' Replace the contents of the hold space with the contents of the pattern space. -`H' - Append a newline to the contents of the hold space, and then - append the contents of the pattern space to that of the hold space. +'H' + Append a newline to the contents of the hold space, and then append + the contents of the pattern space to that of the hold space. -`g' +'g' Replace the contents of the pattern space with the contents of the hold space. -`G' +'G' Append a newline to the contents of the pattern space, and then append the contents of the hold space to that of the pattern space. -`x' +'x' Exchange the contents of the hold and pattern spaces. - ---------- Footnotes ---------- - (1) This is equivalent to `p' unless the `-i' option is being used. + (1) This is equivalent to 'p' unless the '-i' option is being used. -File: sed.info, Node: Programming Commands, Next: Extended Commands, Prev: Other Commands, Up: sed Programs +File: sed.info-t, Node: Programming Commands, Next: Extended Commands, Prev: Other Commands, Up: sed scripts -3.7 Commands for `sed' gurus +3.6 Commands for 'sed' gurus ============================ In most cases, use of these commands indicates that you are probably -better off programming in something like `awk' or Perl. But -occasionally one is committed to sticking with `sed', and these -commands can enable one to write quite convoluted scripts. +better off programming in something like 'awk' or Perl. But +occasionally one is committed to sticking with 'sed', and these commands +can enable one to write quite convoluted scripts. -`: LABEL' +': LABEL' [No addresses allowed.] Specify the location of LABEL for branch commands. In all other respects, a no-op. -`b LABEL' +'b LABEL' Unconditionally branch to LABEL. The LABEL may be omitted, in which case the next cycle is started. -`t LABEL' - Branch to LABEL only if there has been a successful `s'ubstitution +'t LABEL' + Branch to LABEL only if there has been a successful 's'ubstitution since the last input line was read or conditional branch was taken. The LABEL may be omitted, in which case the next cycle is started. - -File: sed.info, Node: Extended Commands, Next: Escapes, Prev: Programming Commands, Up: sed Programs +File: sed.info-t, Node: Extended Commands, Prev: Programming Commands, Up: sed scripts -3.8 Commands Specific to GNU `sed' +3.7 Commands Specific to GNU 'sed' ================================== -These commands are specific to GNU `sed', so you must use them with -care and only when you are sure that hindering portability is not evil. -They allow you to check for GNU `sed' extensions or to do tasks that -are required quite often, yet are unsupported by standard `sed's. +These commands are specific to GNU 'sed', so you must use them with care +and only when you are sure that hindering portability is not evil. They +allow you to check for GNU 'sed' extensions or to do tasks that are +required quite often, yet are unsupported by standard 'sed's. -`e [COMMAND]' +'e [COMMAND]' This command allows one to pipe input from a shell command into - pattern space. Without parameters, the `e' command executes the + pattern space. Without parameters, the 'e' command executes the command that is found in pattern space and replaces the pattern space with the output; a trailing newline is suppressed. - If a parameter is specified, instead, the `e' command interprets - it as a command and sends its output to the output stream. The + If a parameter is specified, instead, the 'e' command interprets it + as a command and sends its output to the output stream. The command can run across multiple lines, all but the last ending with a back-slash. In both cases, the results are undefined if the command to be executed contains a NUL character. - Note that, unlike the `r' command, the output of the command will - be printed immediately; the `r' command instead delays the output + Note that, unlike the 'r' command, the output of the command will + be printed immediately; the 'r' command instead delays the output to the end of the current cycle. -`F' +'F' Print out the file name of the current input file (with a trailing newline). -`L N' - This GNU `sed' extension fills and joins lines in pattern space to - produce output lines of (at most) N characters, like `fmt' does; - if N is omitted, the default as specified on the command line is - used. This command is considered a failed experiment and unless - there is enough request (which seems unlikely) will be removed in - future versions. - -`Q [EXIT-CODE]' +'Q [EXIT-CODE]' This command only accepts a single address. - This command is the same as `q', but will not print the contents - of pattern space. Like `q', it provides the ability to return an - exit code to the caller. + This command is the same as 'q', but will not print the contents of + pattern space. Like 'q', it provides the ability to return an exit + code to the caller. This command can be useful because the only alternative ways to - accomplish this apparently trivial function are to use the `-n' + accomplish this apparently trivial function are to use the '-n' option (which can unnecessarily complicate your script) or resorting to the following snippet, which wastes time by reading the whole file without any visible effect: @@ -1064,159 +1181,1204 @@ are required quite often, yet are unsupported by standard `sed's. g Overwrite pattern space each time to save memory b eat -`R FILENAME' +'R FILENAME' Queue a line of FILENAME to be read and inserted into the output - stream at the end of the current cycle, or when the next input - line is read. Note that if FILENAME cannot be read, or if its end - is reached, no line is appended, without any error indication. + stream at the end of the current cycle, or when the next input line + is read. Note that if FILENAME cannot be read, or if its end is + reached, no line is appended, without any error indication. - As with the `r' command, the special value `/dev/stdin' is + As with the 'r' command, the special value '/dev/stdin' is supported for the file name, which reads a line from the standard input. -`T LABEL' +'T LABEL' Branch to LABEL only if there have been no successful - `s'ubstitutions since the last input line was read or conditional - branch was taken. The LABEL may be omitted, in which case the next + 's'ubstitutions since the last input line was read or conditional + branch was taken. The LABEL may be omitted, in which case the next cycle is started. -`v VERSION' - This command does nothing, but makes `sed' fail if GNU `sed' +'v VERSION' + This command does nothing, but makes 'sed' fail if GNU 'sed' extensions are not supported, simply because other versions of - `sed' do not implement it. In addition, you can specify the - version of `sed' that your script requires, such as `4.0.5'. The - default is `4.0' because that is the first version that - implemented this command. + 'sed' do not implement it. In addition, you can specify the + version of 'sed' that your script requires, such as '4.0.5'. The + default is '4.0' because that is the first version that implemented + this command. - This command enables all GNU extensions even if `POSIXLY_CORRECT' + This command enables all GNU extensions even if 'POSIXLY_CORRECT' is set in the environment. -`W FILENAME' +'W FILENAME' Write to the given filename the portion of the pattern space up to - the first newline. Everything said under the `w' command about + the first newline. Everything said under the 'w' command about file handling holds here too. -`z' +'z' This command empties the content of pattern space. It is usually - the same as `s/.*//', but is more efficient and works in the - presence of invalid multibyte sequences in the input stream. - POSIX mandates that such sequences are _not_ matched by `.', so - that there is no portable way to clear `sed''s buffers in the - middle of the script in most multibyte locales (including UTF-8 - locales). + the same as 's/.*//', but is more efficient and works in the + presence of invalid multibyte sequences in the input stream. POSIX + mandates that such sequences are _not_ matched by '.', so that + there is no portable way to clear 'sed''s buffers in the middle of + the script in most multibyte locales (including UTF-8 locales). + + +File: sed.info-t, Node: sed addresses, Next: sed regular expressions, Prev: sed scripts, Up: Top + +4 Addresses: selecting lines +**************************** + +* Menu: + +* Addresses overview:: Addresses overview +* Numeric Addresses:: selecting lines by numbers +* Regexp Addresses:: selecting lines by text matching +* Range Addresses:: selecting a range of lines + + +File: sed.info-t, Node: Addresses overview, Next: Numeric Addresses, Up: sed addresses + +4.1 Addresses overview +====================== + +Addresses determine on which line(s) the 'sed' command will be executed. +The following command replaces the word 'hello' with 'world' only on +line 144: + + sed '144s/hello/world/' input.txt > output.txt + + If no addresses are given, the command is performed on all lines. +The following command replaces the word 'hello' with 'world' on all +lines in the input file: + + sed 's/hello/world/' input.txt > output.txt + + Addresses can contain regular expressions to match lines based on +content instead of line numbers. The following command replaces the +word 'hello' with 'world' only in lines containing the word 'apple': + + sed '/apple/s/hello/world/' input.txt > output.txt + + An address range is specified with two addresses separated by a comma +(','). Addresses can be numeric, regular expressions, or a mix of both. +The following command replaces the word 'hello' with 'world' only in +lines 4 to 17 (inclusive): + + sed '4,17s/hello/world/' input.txt > output.txt + + Appending the '!' character to the end of an address specification +(before the command letter) negates the sense of the match. That is, if +the '!' character follows an address or an address range, then only +lines which do _not_ match the addresses will be selected. The +following command replaces the word 'hello' with 'world' only in lines +_not_ containing the word 'apple': + + sed '/apple/!s/hello/world/' input.txt > output.txt + + The following command replaces the word 'hello' with 'world' only in +lines 1 to 3 and 18 till the last line of the input file (i.e. +excluding lines 4 to 17): + + sed '4,17!s/hello/world/' input.txt > output.txt + + +File: sed.info-t, Node: Numeric Addresses, Next: Regexp Addresses, Prev: Addresses overview, Up: sed addresses + +4.2 Selecting lines by numbers +============================== + +Addresses in a 'sed' script can be in any of the following forms: +'NUMBER' + Specifying a line number will match only that line in the input. + (Note that 'sed' counts lines continuously across all input files + unless '-i' or '-s' options are specified.) + +'$' + This address matches the last line of the last file of input, or + the last line of each file when the '-i' or '-s' options are + specified. + +'FIRST~STEP' + This GNU extension matches every STEPth line starting with line + FIRST. In particular, lines will be selected when there exists a + non-negative N such that the current line-number equals FIRST + (N + * STEP). Thus, one would use '1~2' to select the odd-numbered + lines and '0~2' for even-numbered lines; to pick every third line + starting with the second, '2~3' would be used; to pick every fifth + line starting with the tenth, use '10~5'; and '50~0' is just an + obscure way of saying '50'. + + The following commands demonstrate the step address usage: + + $ seq 10 | sed -n '0~4p' + 4 + 8 + + $ seq 10 | sed -n '1~3p' + 1 + 4 + 7 + 10 + + +File: sed.info-t, Node: Regexp Addresses, Next: Range Addresses, Prev: Numeric Addresses, Up: sed addresses + +4.3 selecting lines by text matching +==================================== + +GNU 'sed' supports the following regular expression addresses. The +default regular expression is *note Basic Regular Expression (BRE): BRE +syntax. If '-E' or '-r' options are used, The regular expression should +be in *note Extended Regular Expression (ERE): ERE syntax. syntax. +*Note BRE vs ERE::. + +'/REGEXP/' + This will select any line which matches the regular expression + REGEXP. If REGEXP itself includes any '/' characters, each must be + escaped by a backslash ('\'). + + The following command prints lines in '/etc/passwd' which end with + 'bash'(1): + + sed -n '/bash$/p' /etc/passwd + + The empty regular expression '//' repeats the last regular + expression match (the same holds if the empty regular expression is + passed to the 's' command). Note that modifiers to regular + expressions are evaluated when the regular expression is compiled, + thus it is invalid to specify them together with the empty regular + expression. + +'\%REGEXP%' + (The '%' may be replaced by any other single character.) + + This also matches the regular expression REGEXP, but allows one to + use a different delimiter than '/'. This is particularly useful if + the REGEXP itself contains a lot of slashes, since it avoids the + tedious escaping of every '/'. If REGEXP itself includes any + delimiter characters, each must be escaped by a backslash ('\'). + + The following two commands are equivalent. They print lines which + start with '/home/alice/documents/': + + sed -n '/^\/home\/alice\/documents\//p' + sed -n '\%^/home/alice/documents/%p' + sed -n '\;^/home/alice/documents/;p' + +'/REGEXP/I' +'\%REGEXP%I' + The 'I' modifier to regular-expression matching is a GNU extension + which causes the REGEXP to be matched in a case-insensitive manner. + + In many other programming languages, a lower case 'i' is used for + case-insensitive regular expression matching. However, in 'sed' + the 'i' is used for the insert command (TODO: add 'pxref'). + + Observe the difference between the following examples. + + In this example, '/b/I' is the address: regular expression with 'I' + modifier. 'd' is the delete command: + + $ printf "%s\n" a b c | sed '/b/Id' + a + c + + Here, '/b/' is the address: a regular expression. 'i' is the + insert command. 'd' is the value to insert. A line with 'd' is + then inserted above the matched line: + + $ printf "%s\n" a b c | sed '/b/id' + a + d + b + c + +'/REGEXP/M' +'\%REGEXP%M' + The 'M' modifier to regular-expression matching is a GNU 'sed' + extension which directs GNU 'sed' to match the regular expression + in 'multi-line' mode. The modifier causes '^' and '$' to match + respectively (in addition to the normal behavior) the empty string + after a newline, and the empty string before a newline. There are + special character sequences ('\`' and '\'') which always match the + beginning or the end of the buffer. In addition, the period + character does not match a new-line character in multi-line mode. + + ---------- Footnotes ---------- + + (1) There are of course many other ways to do the same, e.g. + grep 'bash$' /etc/passwd + awk -F: '$7 == "/bin/bash"' /etc/passwd -File: sed.info, Node: Escapes, Prev: Extended Commands, Up: sed Programs +File: sed.info-t, Node: Range Addresses, Prev: Regexp Addresses, Up: sed addresses + +4.4 Range Addresses +=================== + +An address range can be specified by specifying two addresses separated +by a comma (','). An address range matches lines starting from where +the first address matches, and continues until the second address +matches (inclusively): + + $ seq 10 | sed -n '4,6p' + 4 + 5 + 6 + + If the second address is a REGEXP, then checking for the ending match +will start with the line _following_ the line which matched the first +address: a range will always span at least two lines (except of course +if the input stream ends). + + $ seq 10 | sed -n '4,/[0-9]/p' + 4 + 5 -3.9 GNU Extensions for Escapes in Regular Expressions + If the second address is a NUMBER less than (or equal to) the line +matching the first address, then only the one line is matched: + + $ seq 10 | sed -n '4,1p' + 4 + + GNU 'sed' also supports some special two-address forms; all these are +GNU extensions: +'0,/REGEXP/' + A line number of '0' can be used in an address specification like + '0,/REGEXP/' so that 'sed' will try to match REGEXP in the first + input line too. In other words, '0,/REGEXP/' is similar to + '1,/REGEXP/', except that if ADDR2 matches the very first line of + input the '0,/REGEXP/' form will consider it to end the range, + whereas the '1,/REGEXP/' form will match the beginning of its range + and hence make the range span up to the _second_ occurrence of the + regular expression. + + Note that this is the only place where the '0' address makes sense; + there is no 0-th line and commands which are given the '0' address + in any other way will give an error. + + The following examples demonstrate the difference between starting + with address 1 and 0: + + $ seq 10 | sed -n '1,/[0-9]/p' + 1 + 2 + + $ seq 10 | sed -n '0,/[0-9]/p' + 1 + +'ADDR1,+N' + Matches ADDR1 and the N lines following ADDR1. + + $ seq 10 | sed -n '6,+2p' + 6 + 7 + 8 + + ADDR1 can be a line number or a regular expression. + +'ADDR1,~N' + Matches ADDR1 and the lines following ADDR1 until the next line + whose input line number is a multiple of N. The following command + prints starting at line 6, until the next line which is a multiple + of 4 (i.e. line 8): + + $ seq 10 | sed -n '6,~4p' + 6 + 7 + 8 + + ADDR1 can be a line number or a regular expression. + + +File: sed.info-t, Node: sed regular expressions, Next: advanced sed, Prev: sed addresses, Up: Top + +5 Regular Expressions: selecting text +************************************* + +* Menu: + +* Regular Expressions Overview:: Overview of Regular expression in 'sed' +* BRE vs ERE:: Basic (BRE) and extended (ERE) regular expression + syntax +* BRE syntax:: Overview of basic regular expression syntax +* ERE syntax:: Overview of extended regular expression syntax +* Character Classes and Bracket Expressions:: +* regexp extensions:: Additional regular expression commands +* Back-references and Subexpressions:: Back-references and Subexpressions +* Escapes:: Specifying special characters +* Locale Considerations:: + + +File: sed.info-t, Node: Regular Expressions Overview, Next: BRE vs ERE, Up: sed regular expressions + +5.1 Overview of regular expression in 'sed' +=========================================== + +To know how to use 'sed', people should understand regular expressions +("regexp" for short). A regular expression is a pattern that is matched +against a subject string from left to right. Most characters are +"ordinary": they stand for themselves in a pattern, and match the +corresponding characters. Regular expressions in 'sed' are specified +between two slashes. + + The following command prints lines containing the word 'hello': + + sed -n '/hello/p' + + The above example is equivalent to this 'grep' command: + + grep 'hello' + + The power of regular expressions comes from the ability to include +alternatives and repetitions in the pattern. These are encoded in the +pattern by the use of "special characters", which do not stand for +themselves but instead are interpreted in some special way. + + The character '^' (caret) in a regular expression matches the +beginning of the line. The character '.' (dot) matches any single +character. The following 'sed' command matches and prints lines which +start with the letter 'b', followed by any single character, followed by +the letter 'd': + + $ printf "%s\n" abode bad bed bit bid byte body | sed -n '/^b.d/p' + bad + bed + bid + body + + The following sections explain the meaning and usage of special +characters in regular expressions. + + +File: sed.info-t, Node: BRE vs ERE, Next: BRE syntax, Prev: Regular Expressions Overview, Up: sed regular expressions + +5.2 Basic (BRE) and extended (ERE) regular expression ===================================================== -Until this chapter, we have only encountered escapes of the form `\^', -which tell `sed' not to interpret the circumflex as a special -character, but rather to take it literally. For example, `\*' matches -a single asterisk rather than zero or more backslashes. +Basic and extended regular expressions are two variations on the syntax +of the specified pattern. Basic Regular Expression (BRE) is the default +in 'sed' (and similarly in 'grep'). Extended Regular Expression syntax +(ERE) is activated by using the '-r' or '-E' options (and similarly, +'grep -E'). + + In GNU 'sed' the only difference between basic and extended regular +expressions is in the behavior of a few special characters: '?', '+', +parentheses, braces ('{}'), and '|'. + + With basic (BRE) syntax, these characters do not have special meaning +unless prefixed backslash ('\'); While with extended (ERE) syntax it is +reversed: these characters are special unless they are prefixed with +backslash ('\'). + +Desired pattern Basic (BRE) Syntax Extended (ERE) Syntax + +--------------------------------------------------------------------------- +literal '+' (plus $ echo "a+b=c" | sed -n '/a+b/p' $ echo "a+b=c" | sed -E -n '/a\+b/p' +sign) a+b=c a+b=c + +One or more 'a' $ echo "aab" | sed -n '/a\+b/p' $ echo "aab" | sed -E -n '/a+b/p' +characters followed by aab aab +'b' (plus sign as +special +meta-character) + + +File: sed.info-t, Node: BRE syntax, Next: ERE syntax, Prev: BRE vs ERE, Up: sed regular expressions + +5.3 Overview of basic regular expression syntax +=============================================== + +Here is a brief description of regular expression syntax as used in +'sed'. + +'CHAR' + A single ordinary character matches itself. + +'*' + Matches a sequence of zero or more instances of matches for the + preceding regular expression, which must be an ordinary character, + a special character preceded by '\', a '.', a grouped regexp (see + below), or a bracket expression. As a GNU extension, a postfixed + regular expression can also be followed by '*'; for example, 'a**' + is equivalent to 'a*'. POSIX 1003.1-2001 says that '*' stands for + itself when it appears at the start of a regular expression or + subexpression, but many nonGNU implementations do not support this + and portable scripts should instead use '\*' in these contexts. +'.' + Matches any character, including newline. + +'^' + Matches the null string at beginning of the pattern space, i.e. + what appears after the circumflex must appear at the beginning of + the pattern space. + + In most scripts, pattern space is initialized to the content of + each line (*note How 'sed' works: Execution Cycle.). So, it is a + useful simplification to think of '^#include' as matching only + lines where '#include' is the first thing on line--if there are + spaces before, for example, the match fails. This simplification + is valid as long as the original content of pattern space is not + modified, for example with an 's' command. + + '^' acts as a special character only at the beginning of the + regular expression or subexpression (that is, after '\(' or '\|'). + Portable scripts should avoid '^' at the beginning of a + subexpression, though, as POSIX allows implementations that treat + '^' as an ordinary character in that context. + +'$' + It is the same as '^', but refers to end of pattern space. '$' + also acts as a special character only at the end of the regular + expression or subexpression (that is, before '\)' or '\|'), and its + use at the end of a subexpression is not portable. + +'[LIST]' +'[^LIST]' + Matches any single character in LIST: for example, '[aeiou]' + matches all vowels. A list may include sequences like + 'CHAR1-CHAR2', which matches any character between (inclusive) + CHAR1 and CHAR2. *Note Character Classes and Bracket + Expressions::. + +'\+' + As '*', but matches one or more. It is a GNU extension. + +'\?' + As '*', but only matches zero or one. It is a GNU extension. + +'\{I\}' + As '*', but matches exactly I sequences (I is a decimal integer; + for portability, keep it between 0 and 255 inclusive). + +'\{I,J\}' + Matches between I and J, inclusive, sequences. + +'\{I,\}' + Matches more than or equal to I sequences. + +'\(REGEXP\)' + Groups the inner REGEXP as a whole, this is used to: + + * Apply postfix operators, like '\(abcd\)*': this will search + for zero or more whole sequences of 'abcd', while 'abcd*' + would search for 'abc' followed by zero or more occurrences of + 'd'. Note that support for '\(abcd\)*' is required by POSIX + 1003.1-2001, but many non-GNU implementations do not support + it and hence it is not universally portable. + + * Use back references (see below). + +'REGEXP1\|REGEXP2' + Matches either REGEXP1 or REGEXP2. Use parentheses to use complex + alternative regular expressions. The matching process tries each + alternative in turn, from left to right, and the first one that + succeeds is used. It is a GNU extension. + +'REGEXP1REGEXP2' + Matches the concatenation of REGEXP1 and REGEXP2. Concatenation + binds more tightly than '\|', '^', and '$', but less tightly than + the other regular expression operators. + +'\DIGIT' + Matches the DIGIT-th '\(...\)' parenthesized subexpression in the + regular expression. This is called a "back reference". + Subexpressions are implicitly numbered by counting occurrences of + '\(' left-to-right. + +'\n' + Matches the newline character. + +'\CHAR' + Matches CHAR, where CHAR is one of '$', '*', '.', '[', '\', or '^'. + Note that the only C-like backslash sequences that you can portably + assume to be interpreted are '\n' and '\\'; in particular '\t' is + not portable, and matches a 't' under most implementations of + 'sed', rather than a tab character. + + Note that the regular expression matcher is greedy, i.e., matches are +attempted from left to right and, if two or more matches are possible +starting at the same character, it selects the longest. + +Examples: +'abcdef' + Matches 'abcdef'. + +'a*b' + Matches zero or more 'a's followed by a single 'b'. For example, + 'b' or 'aaaaab'. + +'a\?b' + Matches 'b' or 'ab'. + +'a\+b\+' + Matches one or more 'a's followed by one or more 'b's: 'ab' is the + shortest possible match, but other examples are 'aaaab' or 'abbbbb' + or 'aaaaaabbbbbbb'. + +'.*' +'.\+' + These two both match all the characters in a string; however, the + first matches every string (including the empty string), while the + second matches only strings containing at least one character. + +'^main.*(.*)' + This matches a string starting with 'main', followed by an opening + and closing parenthesis. The 'n', '(' and ')' need not be + adjacent. + +'^#' + This matches a string beginning with '#'. + +'\\$' + This matches a string ending with a single backslash. The regexp + contains two backslashes for escaping. + +'\$' + Instead, this matches a string consisting of a single dollar sign, + because it is escaped. + +'[a-zA-Z0-9]' + In the C locale, this matches any ASCII letters or digits. + +'[^ 'tab']\+' + (Here 'tab' stands for a single tab character.) This matches a + string of one or more characters, none of which is a space or a + tab. Usually this means a word. + +'^\(.*\)\n\1$' + This matches a string consisting of two equal substrings separated + by a newline. + +'.\{9\}A$' + This matches nine characters followed by an 'A' at the end of a + line. + +'^.\{15\}A' + This matches the start of a string that contains 16 characters, the + last of which is an 'A'. + + +File: sed.info-t, Node: ERE syntax, Next: Character Classes and Bracket Expressions, Prev: BRE syntax, Up: sed regular expressions + +5.4 Overview of extended regular expression syntax +================================================== + +The only difference between basic and extended regular expressions is in +the behavior of a few characters: '?', '+', parentheses, braces ('{}'), +and '|'. While basic regular expressions require these to be escaped if +you want them to behave as special characters, when using extended +regular expressions you must escape them if you want them _to match a +literal character_. '|' is special here because '\|' is a GNU extension +- standard basic regular expressions do not provide its functionality. + +Examples: +'abc?' + becomes 'abc\?' when using extended regular expressions. It + matches the literal string 'abc?'. + +'c\+' + becomes 'c+' when using extended regular expressions. It matches + one or more 'c's. + +'a\{3,\}' + becomes 'a{3,}' when using extended regular expressions. It + matches three or more 'a's. + +'\(abc\)\{2,3\}' + becomes '(abc){2,3}' when using extended regular expressions. It + matches either 'abcabc' or 'abcabcabc'. + +'\(abc*\)\1' + becomes '(abc*)\1' when using extended regular expressions. + Backreferences must still be escaped when using extended regular + expressions. + +'a\|b' + becomes 'a|b' when using extended regular expressions. It matches + 'a' or 'b'. + + +File: sed.info-t, Node: Character Classes and Bracket Expressions, Next: regexp extensions, Prev: ERE syntax, Up: sed regular expressions + +5.5 Character Classes and Bracket Expressions +============================================= + +A "bracket expression" is a list of characters enclosed by '[' and ']'. +It matches any single character in that list; if the first character of +the list is the caret '^', then it matches any character *not* in the +list. For example, the following command replaces the words 'gray' or +'grey' with 'blue': + + sed 's/gr[ae]y/blue/' + + Bracket expressions can be used in both *note basic: BRE syntax. and +*note extended: ERE syntax. regular expressions (that is, with or +without the '-E'/'-r' options). + + Within a bracket expression, a "range expression" consists of two +characters separated by a hyphen. It matches any single character that +sorts between the two characters, inclusive. In the default C locale, +the sorting sequence is the native character order; for example, '[a-d]' +is equivalent to '[abcd]'. + + Finally, certain named classes of characters are predefined within +bracket expressions, as follows. + + These named classes must be used _inside_ brackets themselves. +Correct usage: + $ echo 1 | sed 's/[[:digit:]]/X/' + X + + Incorrect usage is rejected by newer 'sed' versions. Older versions +accepted it but treated it as a single bracket expression (which is +equivalent to '[dgit:]', that is, only the characters D/G/I/T/:): + # current GNU sed versions - incorrect usage rejected + $ echo 1 | sed 's/[:digit:]/X/' + sed: character class syntax is [[:space:]], not [:space:] + + # older GNU sed versions + $ echo 1 | sed 's/[:digit:]/X/' + 1 + +'[:alnum:]' + Alphanumeric characters: '[:alpha:]' and '[:digit:]'; in the 'C' + locale and ASCII character encoding, this is the same as + '[0-9A-Za-z]'. + +'[:alpha:]' + Alphabetic characters: '[:lower:]' and '[:upper:]'; in the 'C' + locale and ASCII character encoding, this is the same as + '[A-Za-z]'. + +'[:blank:]' + Blank characters: space and tab. + +'[:cntrl:]' + Control characters. In ASCII, these characters have octal codes + 000 through 037, and 177 (DEL). In other character sets, these are + the equivalent characters, if any. + +'[:digit:]' + Digits: '0 1 2 3 4 5 6 7 8 9'. + +'[:graph:]' + Graphical characters: '[:alnum:]' and '[:punct:]'. + +'[:lower:]' + Lower-case letters; in the 'C' locale and ASCII character encoding, + this is 'a b c d e f g h i j k l m n o p q r s t u v w x y z'. + +'[:print:]' + Printable characters: '[:alnum:]', '[:punct:]', and space. + +'[:punct:]' + Punctuation characters; in the 'C' locale and ASCII character + encoding, this is '! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ + ] ^ _ ` { | } ~'. + +'[:space:]' + Space characters: in the 'C' locale, this is tab, newline, vertical + tab, form feed, carriage return, and space. + +'[:upper:]' + Upper-case letters: in the 'C' locale and ASCII character encoding, + this is 'A B C D E F G H I J K L M N O P Q R S T U V W X Y Z'. + +'[:xdigit:]' + Hexadecimal digits: '0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f'. + + Note that the brackets in these class names are part of the symbolic +names, and must be included in addition to the brackets delimiting the +bracket expression. + + Most meta-characters lose their special meaning inside bracket +expressions: + +']' + ends the bracket expression if it's not the first list item. So, + if you want to make the ']' character a list item, you must put it + first. + +'-' + represents the range if it's not first or last in a list or the + ending point of a range. + +'^' + represents the characters not in the list. If you want to make the + '^' character a list item, place it anywhere but first. + + TODO: incorporate this paragraph (copied verbatim from BRE section). + + The characters '$', '*', '.', '[', and '\' are normally not special +within LIST. For example, '[\*]' matches either '\' or '*', because the +'\' is not special here. However, strings like '[.ch.]', '[=a=]', and +'[:space:]' are special within LIST and represent collating symbols, +equivalence classes, and character classes, respectively, and '[' is +therefore special within LIST when it is followed by '.', '=', or ':'. +Also, when not in 'POSIXLY_CORRECT' mode, special escapes like '\n' and +'\t' are recognized within LIST. *Note Escapes::. + +'[.' + represents the open collating symbol. + +'.]' + represents the close collating symbol. + +'[=' + represents the open equivalence class. + +'=]' + represents the close equivalence class. + +'[:' + represents the open character class symbol, and should be followed + by a valid character class name. + +':]' + represents the close character class symbol. + + +File: sed.info-t, Node: regexp extensions, Next: Back-references and Subexpressions, Prev: Character Classes and Bracket Expressions, Up: sed regular expressions + +5.6 regular expression extensions +================================= + +The following sequences have special meaning inside regular expressions +(used in *note addresses: Regexp Addresses. and the 's' command). + + These can be used in both *note basic: BRE syntax. and *note +extended: ERE syntax. regular expressions (that is, with or without the +'-E'/'-r' options). + +'\w' + Matches any "word" character. A "word" character is any letter or + digit or the underscore character. + + $ echo "abc %-= def." | sed 's/\w/X/g' + XXX %-= XXX. + +'\W' + Matches any "non-word" character. + + $ echo "abc %-= def." | sed 's/\W/X/g' + abcXXXXXdefX + +'\b' + Matches a word boundary; that is it matches if the character to the + left is a "word" character and the character to the right is a + "non-word" character, or vice-versa. + + $ echo "abc %-= def." | sed 's/\b/X/g' + XabcX %-= XdefX. + +'\B' + Matches everywhere but on a word boundary; that is it matches if + the character to the left and the character to the right are either + both "word" characters or both "non-word" characters. + + $ echo "abc %-= def." | sed 's/\w/X/g' + aXbXc X%X-X=X dXeXf.X + +'\s' + Matches whitespace characters (spaces and tabs). Newlines embedded + in the pattern/hold spaces will also match: + + $ echo "abc %-= def." | sed 's/\s/X/g' + abcX%-=Xdef. + +'\S' + Matches non-whitespace characters. + + $ echo "abc %-= def." | sed 's/\w/X/g' + XXX XXX XXXX + +'\<' + Matches the beginning of a word. + + $ echo "abc %-= def." | sed 's/\</X/g' + Xabc %-= Xdef. + +'\>' + Matches the end of a word. + + $ echo "abc %-= def." | sed 's/\>/X/g' + abcX %-= defX. + +'\`' + Matches only at the start of pattern space. This is different from + '^' in multi-line mode. + + Compare the following two examples: + + $ printf "a\nb\nc\n" | sed 'N;N;s/^/X/gm' + Xa + Xb + Xc + + $ printf "a\nb\nc\n" | sed 'N;N;s/\`/X/gm' + Xa + b + c + +'\'' + Matches only at the end of pattern space. This is different from + '$' in multi-line mode. + + +File: sed.info-t, Node: Back-references and Subexpressions, Next: Escapes, Prev: regexp extensions, Up: sed regular expressions + +5.7 Back-references and Subexpressions +====================================== + +"back-references" are regular expression commands which refer to a +previous part of the matched regular expression. Back-references are +specified with backslash and a single digit (e.g. '\1'). The part of +the regular expression they refer to is called a "subexpression", and is +designated with parentheses. + + Back-references and subexpressions are used in two cases: in the +regular expression search pattern, and in the REPLACEMENT part of the +'s' command (*note Regular Expression Addresses: Regexp Addresses. and +*note The "s" Command::). + + In a regular expression pattern, back-references are used to match +the same content as a previously matched subexpression. In the +following example, the subexpression is '.' - any single character +(being surrounded by parentheses makes it a subexpression). The +back-reference '\1' asks to match the same content (same character) as +the sub-expression. + + The command below matches words starting with any character, followed +by the letter 'o', followed by the same character as the first. + + $ sed -E -n '/^(.)o\1$/p' /usr/share/dict/words + bob + mom + non + pop + sos + tot + wow + + Multiple subexpressions are automatically numbered from +left-to-right. This command searches for 6-letter palindromes (the +first three letters are 3 subexpressions, followed by 3 back-references +in reverse order): + + $ sed -E -n '/^(.)(.)(.)\3\2\1$/p' /usr/share/dict/words + redder + + In the 's' command, back-references can be used in the REPLACEMENT +part to refer back to subexpressions in the REGEXP part. + + The following example uses two subexpressions in the regular +expression to match two space-separated words. The back-references in +the REPLACEMENT part prints the words in a different order: + + $ echo "James Bond" | sed -E 's/(.*) (.*)/The name is \2, \1 \2./' + The name is Bond, James Bond. + + When used with alternation, if the group does not participate in the +match then the back-reference makes the whole match fail. For example, +'a(.)|b\1' will not match 'ba'. When multiple regular expressions are +given with '-e' or from a file ('-f FILE'), back-references are local to +each expression. + + +File: sed.info-t, Node: Escapes, Next: Locale Considerations, Prev: Back-references and Subexpressions, Up: sed regular expressions + +5.8 Escape Sequences - specifying special characters +==================================================== + +Until this chapter, we have only encountered escapes of the form '\^', +which tell 'sed' not to interpret the circumflex as a special character, +but rather to take it literally. For example, '\*' matches a single +asterisk rather than zero or more backslashes. This chapter introduces another kind of escape(1)--that is, escapes that are applied to a character or sequence of characters that -ordinarily are taken literally, and that `sed' replaces with a special +ordinarily are taken literally, and that 'sed' replaces with a special character. This provides a way of encoding non-printable characters in -patterns in a visible manner. There is no restriction on the -appearance of non-printing characters in a `sed' script but when a -script is being prepared in the shell or by text editing, it is usually -easier to use one of the following escape sequences than the binary -character it represents: +patterns in a visible manner. There is no restriction on the appearance +of non-printing characters in a 'sed' script but when a script is being +prepared in the shell or by text editing, it is usually easier to use +one of the following escape sequences than the binary character it +represents: The list of these escapes is: -`\a' +'\a' Produces or matches a BEL character, that is an "alert" (ASCII 7). -`\f' +'\f' Produces or matches a form feed (ASCII 12). -`\n' +'\n' Produces or matches a newline (ASCII 10). -`\r' +'\r' Produces or matches a carriage return (ASCII 13). -`\t' +'\t' Produces or matches a horizontal tab (ASCII 9). -`\v' +'\v' Produces or matches a so called "vertical tab" (ASCII 11). -`\cX' - Produces or matches `CONTROL-X', where X is any character. The - precise effect of `\cX' is as follows: if X is a lower case - letter, it is converted to upper case. Then bit 6 of the - character (hex 40) is inverted. Thus `\cz' becomes hex 1A, but - `\c{' becomes hex 3B, while `\c;' becomes hex 7B. +'\cX' + Produces or matches 'CONTROL-X', where X is any character. The + precise effect of '\cX' is as follows: if X is a lower case letter, + it is converted to upper case. Then bit 6 of the character (hex + 40) is inverted. Thus '\cz' becomes hex 1A, but '\c{' becomes hex + 3B, while '\c;' becomes hex 7B. -`\dXXX' +'\dXXX' Produces or matches a character whose decimal ASCII value is XXX. -`\oXXX' +'\oXXX' Produces or matches a character whose octal ASCII value is XXX. -`\xXX' +'\xXX' Produces or matches a character whose hexadecimal ASCII value is XX. - `\b' (backspace) was omitted because of the conflict with the + '\b' (backspace) was omitted because of the conflict with the existing "word boundary" meaning. - Other escapes match a particular character class and are valid only -in regular expressions: + ---------- Footnotes ---------- -`\w' - Matches any "word" character. A "word" character is any letter or - digit or the underscore character. + (1) All the escapes introduced here are GNU extensions, with the +exception of '\n'. In basic regular expression mode, setting +'POSIXLY_CORRECT' disables them inside bracket expressions. -`\W' - Matches any "non-word" character. + +File: sed.info-t, Node: Locale Considerations, Prev: Escapes, Up: sed regular expressions -`\b' - Matches a word boundary; that is it matches if the character to - the left is a "word" character and the character to the right is a - "non-word" character, or vice-versa. +5.9 Locale Considerations +========================= -`\B' - Matches everywhere but on a word boundary; that is it matches if - the character to the left and the character to the right are - either both "word" characters or both "non-word" characters. +TODO: fix following paragraphs (copied verbatim from 'bracket +expression' section). -`\`' - Matches only at the start of pattern space. This is different - from `^' in multi-line mode. + TODO: mention locale support is heavily dependent on the OS/libc, not +on sed. -`\'' - Matches only at the end of pattern space. This is different from - `$' in multi-line mode. + The current locale affects the characters matched by 'sed''s regular +expressions. + + In other locales, the sorting sequence is not specified, and '[a-d]' +might be equivalent to '[abcd]' or to '[aBbCcDd]', or it might fail to +match any character, or the set of characters that it matches might even +be erratic. To obtain the traditional interpretation of bracket +expressions, you can use the 'C' locale by setting the 'LC_ALL' +environment variable to the value 'C'. + + # TODO: is there any real-world system/locale where 'A' + # is replaced by '-' ? + $ echo A | sed 's/[a-z]/-/' + A + + Their interpretation depends on the 'LC_CTYPE' locale; for example, +'[[:alnum:]]' means the character class of numbers and letters in the +current locale. + + TODO: show example of collation + + # TODO: this works on glibc systems, not on musl-libc/freebsd/macosx. + $ printf 'cliché\n' | LC_ALL=fr_FR.utf8 sed 's/[[=e=]]/X/g' + clichX + + +File: sed.info-t, Node: advanced sed, Next: Examples, Prev: sed regular expressions, Up: Top + +6 Advanced 'sed': cycles and buffers +************************************ + +* Menu: + +* Execution Cycle:: How 'sed' works +* Hold and Pattern Buffers:: +* Multiline techniques:: Using D,G,H,N,P to process multiple lines +* Branching and flow control:: + + +File: sed.info-t, Node: Execution Cycle, Next: Hold and Pattern Buffers, Up: advanced sed + +6.1 How 'sed' Works +=================== + +'sed' maintains two data buffers: the active _pattern_ space, and the +auxiliary _hold_ space. Both are initially empty. + + 'sed' operates by performing the following cycle on each line of +input: first, 'sed' reads one line from the input stream, removes any +trailing newline, and places it in the pattern space. Then commands are +executed; each command can have an address associated to it: addresses +are a kind of condition code, and a command is only executed if the +condition is verified before the command is to be executed. + When the end of the script is reached, unless the '-n' option is in +use, the contents of pattern space are printed out to the output stream, +adding back the trailing newline if it was removed.(1) Then the next +cycle starts for the next input line. + + Unless special commands (like 'D') are used, the pattern space is +deleted between two cycles. The hold space, on the other hand, keeps +its data between cycles (see commands 'h', 'H', 'x', 'g', 'G' to move +data between both buffers). ---------- Footnotes ---------- - (1) All the escapes introduced here are GNU extensions, with the -exception of `\n'. In basic regular expression mode, setting -`POSIXLY_CORRECT' disables them inside bracket expressions. + (1) Actually, if 'sed' prints a line without the terminating newline, +it will nevertheless print the missing newline as soon as more text is +sent to the same output stream, which gives the "least expected +surprise" even though it does not make commands like 'sed -n p' exactly +identical to 'cat'. + + +File: sed.info-t, Node: Hold and Pattern Buffers, Next: Multiline techniques, Prev: Execution Cycle, Up: advanced sed + +6.2 Hold and Pattern Buffers +============================ + +TODO + + +File: sed.info-t, Node: Multiline techniques, Next: Branching and flow control, Prev: Hold and Pattern Buffers, Up: advanced sed + +6.3 Multiline techniques - using D,G,H,N,P to process multiple lines +==================================================================== + +Multiple lines can be processed as one buffer using the +'D','G','H','N','P'. They are similar to their lowercase counterparts +('d','g', 'h','n','p'), except that these commands append or subtract +data while respecting embedded newlines - allowing adding and removing +lines from the pattern and hold spaces. + + They operate as follows: +'D' + _deletes_ line from the pattern space until the first newline, and + restarts the cycle. + +'G' + _appends_ line from the hold space to the pattern space, with a + newline before it. + +'H' + _appends_ line from the pattern space to the hold space, with a + newline before it. + +'N' + _appends_ line from the input file to the pattern space. + +'P' + _prints_ line from the pattern space until the first newline. + + The following example illustrates the operation of 'N' and 'D' +commands: + + $ seq 6 | sed -n 'N;l;D' + 1\n2$ + 2\n3$ + 3\n4$ + 4\n5$ + 5\n6$ + + 1. 'sed' starts by reading the first line into the pattern space (i.e. + '1'). + 2. At the beginning of every cycle, the 'N' command appends a newline + and the next line to the pattern space (i.e. '1', '\n', '2' in the + first cycle). + 3. The 'l' command prints the content of the pattern space + unambigiously. + 4. The 'D' command then removes the content of pattern space up to the + first newline (leaving '2' at the end of the first cycle). + 5. At the next cycle the 'N' command appends a newline and the next + input line to the pattern space (e.g. '2', '\n', '3'). + + A common technique to process blocks of text such as paragraphs +(instead of line-by-line) is using the following construct: + + sed '/./{H;$!d} ; x ; s/REGEXP/REPLACEMENT/' + + 1. The first expression, '/./{H;$!d}' operates on all non-empty lines, + and adds the current line (in the pattern space) to the hold space. + On all lines except the last, the pattern space is deleted and the + cycle is restarted. + + 2. The other expressions 'x' and 's' are executed only on empty lines + (i.e. paragraph separators). The 'x' command fetches the + accumulated lines from the hold space back to the pattern space. + The 's///' command then operates on all the text in the paragraph + (including the embedded newlines). + + The following example demonstrates this technique: + $ cat input.txt + a a a aa aaa + aaaa aaaa aa + aaaa aaa aaa + + bbbb bbb bbb + bb bb bbb bb + bbbbbbbb bbb + + ccc ccc cccc + cccc ccccc c + cc cc cc cc + + $ sed '/./{H;$!d} ; x ; s/^/\nSTART-->/ ; s/$/\n<--END/' input.txt + + START--> + a a a aa aaa + aaaa aaaa aa + aaaa aaa aaa + <--END + + START--> + bbbb bbb bbb + bb bb bbb bb + bbbbbbbb bbb + <--END + + START--> + ccc ccc cccc + cccc ccccc c + cc cc cc cc + <--END + + For more annotated examples, *note Text search across multiple +lines:: and *note Line length adjustment::. -File: sed.info, Node: Examples, Next: Limitations, Prev: sed Programs, Up: Top +File: sed.info-t, Node: Branching and flow control, Prev: Multiline techniques, Up: advanced sed -4 Some Sample Scripts +6.4 Branching and Flow Control +============================== + +TODO + + +File: sed.info-t, Node: Examples, Next: Limitations, Prev: advanced sed, Up: Top + +7 Some Sample Scripts ********************* -Here are some `sed' scripts to guide you in the art of mastering `sed'. +Here are some 'sed' scripts to guide you in the art of mastering 'sed'. * Menu: + +Useful one-liners: +* Joining lines:: + Some exotic examples: * Centering lines:: * Increment a number:: * Rename files to lower case:: * Print bash environment:: * Reverse chars of lines:: +* Text search across multiple lines:: +* Line length adjustment:: Emulating standard utilities: * tac:: Reverse lines of files @@ -1233,13 +2395,51 @@ Emulating standard utilities: * cat -s:: Squeezing blank lines -File: sed.info, Node: Centering lines, Next: Increment a number, Up: Examples +File: sed.info-t, Node: Joining lines, Next: Centering lines, Up: Examples + +7.1 Joining lines +================= + +Join specific lines (e.g. if lines 2 and 3 need to be joined): + + $ cat lines.txt + hello + hel + lo + hello + + $ sed '2{N;s/\n//;}' lines.txt + hello + hello + hello -4.1 Centering Lines + Join lines ending with backslashes: + + $ cat 1.txt + this \ + is \ + a \ + long \ + line + and another \ + line + + $ sed -e ':x /\\$/ { N; s/\\\n//g ; bx }' 1.txt + this is a long line + and another line + + + #TODO: The above requires gnu sed. + # non-gnu seds need newlines after ':' and 'b' + + +File: sed.info-t, Node: Centering lines, Next: Increment a number, Prev: Joining lines, Up: Examples + +7.2 Centering Lines =================== This script centers all lines of a file on a 80 columns width. To -change that width, the number in `\{...\}' must be replaced, and the +change that width, the number in '\{...\}' must be replaced, and the number of added spaces also must be changed. Note how the buffer commands are used to separate parts in the @@ -1255,7 +2455,7 @@ regular expressions to be matched--this is a common technique. x } - # del leading and trailing spaces + # delete leading and trailing spaces y/tab/ / s/^ *// s/ *$// @@ -1270,25 +2470,25 @@ regular expressions to be matched--this is a common technique. s/^\(.*\)\n\(.*\)\2/\2\1/ -File: sed.info, Node: Increment a number, Next: Rename files to lower case, Prev: Centering lines, Up: Examples +File: sed.info-t, Node: Increment a number, Next: Rename files to lower case, Prev: Centering lines, Up: Examples -4.2 Increment a Number +7.3 Increment a Number ====================== This script is one of a few that demonstrate how to do arithmetic in -`sed'. This is indeed possible,(1) but must be done manually. +'sed'. This is indeed possible,(1) but must be done manually. - To increment one number you just add 1 to last digit, replacing it -by the following digit. There is one exception: when the digit is a -nine the previous digits must be also incremented until you don't have -a nine. + To increment one number you just add 1 to last digit, replacing it by +the following digit. There is one exception: when the digit is a nine +the previous digits must be also incremented until you don't have a +nine. This solution by Bruno Haible is very clever and smart because it uses a single buffer; if you don't have this limitation, the algorithm -used in *note Numbering lines: cat -n, is faster. It works by -replacing trailing nines with an underscore, then using multiple `s' -commands to increment the last digit, and then again substituting -underscores with zeros. +used in *note Numbering lines: cat -n, is faster. It works by replacing +trailing nines with an underscore, then using multiple 's' commands to +increment the last digit, and then again substituting underscores with +zeros. #!/usr/bin/sed -f @@ -1319,24 +2519,24 @@ underscores with zeros. ---------- Footnotes ---------- - (1) `sed' guru Greg Ubben wrote an implementation of the `dc' RPN + (1) 'sed' guru Greg Ubben wrote an implementation of the 'dc' RPN calculator! It is distributed together with sed. -File: sed.info, Node: Rename files to lower case, Next: Print bash environment, Prev: Increment a number, Up: Examples +File: sed.info-t, Node: Rename files to lower case, Next: Print bash environment, Prev: Increment a number, Up: Examples -4.3 Rename Files to Lower Case +7.4 Rename Files to Lower Case ============================== -This is a pretty strange use of `sed'. We transform text, and -transform it to be shell commands, then just feed them to shell. Don't -worry, even worse hacks are done when using `sed'; I have seen a script -converting the output of `date' into a `bc' program! +This is a pretty strange use of 'sed'. We transform text, and transform +it to be shell commands, then just feed them to shell. Don't worry, +even worse hacks are done when using 'sed'; I have seen a script +converting the output of 'date' into a 'bc' program! - The main body of this is the `sed' script, which remaps the name -from lower to upper (or vice-versa) and even checks out if the remapped -name is the same as the original name. Note how the script is -parameterized using shell variables and proper quoting. + The main body of this is the 'sed' script, which remaps the name from +lower to upper (or vice-versa) and even checks out if the remapped name +is the same as the original name. Note how the script is parameterized +using shell variables and proper quoting. #! /bin/sh # rename files to lower/upper case... @@ -1435,13 +2635,13 @@ parameterized using shell variables and proper quoting. ' | $apply_cmd -File: sed.info, Node: Print bash environment, Next: Reverse chars of lines, Prev: Rename files to lower case, Up: Examples +File: sed.info-t, Node: Print bash environment, Next: Reverse chars of lines, Prev: Rename files to lower case, Up: Examples -4.4 Print `bash' Environment +7.5 Print 'bash' Environment ============================ -This script strips the definition of the shell functions from the -output of the `set' Bourne-shell command. +This script strips the definition of the shell functions from the output +of the 'set' Bourne-shell command. #!/bin/sh @@ -1469,20 +2669,20 @@ output of the `set' Bourne-shell command. ' -File: sed.info, Node: Reverse chars of lines, Next: tac, Prev: Print bash environment, Up: Examples +File: sed.info-t, Node: Reverse chars of lines, Next: Text search across multiple lines, Prev: Print bash environment, Up: Examples -4.5 Reverse Characters of Lines +7.6 Reverse Characters of Lines =============================== This script can be used to reverse the position of characters in lines. The technique moves two characters at a time, hence it is faster than more intuitive implementations. - Note the `tx' command before the definition of the label. This is -often needed to reset the flag that is tested by the `t' command. + Note the 'tx' command before the definition of the label. This is +often needed to reset the flag that is tested by the 't' command. Imaginative readers will find uses for this script. An example is -reversing the output of `banner'.(1) +reversing the output of 'banner'.(1) #!/usr/bin/sed -f @@ -1515,16 +2715,167 @@ example ~/sedscripts/reverseline.sed -File: sed.info, Node: tac, Next: cat -n, Prev: Reverse chars of lines, Up: Examples +File: sed.info-t, Node: Text search across multiple lines, Next: Line length adjustment, Prev: Reverse chars of lines, Up: Examples + +7.7 Text search across multiple lines +===================================== + +This section uses 'N' and 'D' commands to search for consecutive words +spanning multiple lines. *Note Multiline techniques::. + + These examples deal with finding doubled occurrences of words in a +document. + + Finding doubled words in a single line is easy using GNU 'grep' and +similarly with GNU 'sed': + + $ cat two-cities-dup1.txt + It was the best of times, + it was the worst of times, + it was the the age of wisdom, + it was the age of foolishness, + + $ grep -E '\b(\w+)\s+\1\b' two-cities-dup1.txt + it was the the age of wisdom, + + $ grep -n -E '\b(\w+)\s+\1\b' two-cities-dup1.txt + 3:it was the the age of wisdom, + + $ sed -En '/\b(\w+)\s+\1\b/p' two-cities-dup1.txt + it was the the age of wisdom, + + $ sed -En '/\b(\w+)\s+\1\b/{=;p}' two-cities-dup1.txt + 3 + it was the the age of wisdom, + + * The regular expression '\b\w+\s+' searches for word-boundary + ('\b'), followed by one-or-more word-characters ('\w+'), followed + by whitespace ('\s+'). *Note regexp extensions::. + + * Adding parentheses around the '(\w+)' expression creates a + subexpression. The regular expression pattern '(PATTERN)\s+\1' + defines a subexpression (in the parentheses) followed by a + back-reference, separated by whitespace. A successful match means + the PATTERN was repeated twice in succession. *Note + Back-references and Subexpressions::. + + * The word-boundery expression ('\b') at both ends ensures partial + words are not matched (e.g. 'the then' is not a desired match). + + * The '-E' option enables extended regular expression syntax, + alleviating the need to add backslashes before the parenthesis. + *Note ERE syntax::. + + When the doubled word span two lines the above regular expression +will not find them as 'grep' and 'sed' operate line-by-line. + + By using 'N' and 'D' commands, 'sed' can apply regular expressions on +multiple lines (that is, multiple lines are stored in the pattern space, +and the regular expression works on it): + + $ cat two-cities-dup2.txt + It was the best of times, it was the + worst of times, it was the + the age of wisdom, + it was the age of foolishness, + + $ sed -En '{N; /\b(\w+)\s+\1\b/{=;p} ; D}' two-cities-dup2.txt + 3 + worst of times, it was the + the age of wisdom, + + * The 'N' command appends the next line to the pattern space (thus + ensuring it contains two consecutive lines in every cycle). + + * The regular expression uses '\s+' for word separator which matches + both spaces and newlines. + + * The regular expression matches, the entire pattern space is printed + with 'p'. No lines are printed by default due to the '-n' option. + + * The 'D' removes the first line from the pattern space (up until the + first newline), readying it for the next cycle. + + See the GNU 'coreutils' manual for an alternative solution using 'tr +-s' and 'uniq' at +<https://gnu.org/s/coreutils/manual/html_node/Squeezing-and-deleting.html>. + + +File: sed.info-t, Node: Line length adjustment, Next: tac, Prev: Text search across multiple lines, Up: Examples -4.6 Reverse Lines of Files +7.8 Line length adjustment +========================== + +This section uses 'N' and 'D' commands to search for consecutive words +spanning multiple lines, and the 'b' command for branching. *Note +Multiline techniques:: and *note Branching and flow control::. + + These (somewhat contrived) examples deal with formatting and wrapping +lines of text of the following input file: + + $ cat two-cities-mix.txt + It was the best of times, it was + the worst of times, it + was the age of + wisdom, + it + was + the age + of foolishness, + + The following command will wrap lines at 40 characters: + $ sed -E ':x {N ; s/\n/ /g ; s/(.{40,40})/\1\n/ ; /\n/!bx ; P ; D}' \ + two-cities-mix.txt + It was the best of times, it was the wor + st of times, it was the age of wisdom, i + t was the age of foolishness, + + The following command will split lines by comma character: + $ sed -E ':x {N ; s/\n/ /g ; s/,/,\n/ ; /\n/!bx ; s/^ *// ; P ; D}' \ + two-cities-mix.txt + It was the best of times, + it was the worst of times, + it was the age of wisdom, + it was the age of foolishness, + + Both examples use similar construct: + + * The ':x' is a label. It will be used later by the 'b' command to + jump to the beginning of the 'sed' program without starting a new + cycle. + + * The 'N' command reads the next line from the input file, and + appends it to the existing content of the pattern space (with a + newline preceding it). + + * The first 's/\n/ /g' command replaces all newlines with spaces, + discarding the line structure of the input file. + + * The second 's///' command adds newlines based on the desired + pattern (after 40 characters in the first example, after comma + character in the second example). + + * The '/\n/!bx' command searches for a newline in the pattern space + ('/n/'), and if it is _not_ found ('!'), branches (=jumps) to the + previously defined label 'x'. This will cause 'sed' to read the + next line without processing any further commands in this cycle. + + * If a newline is found in the pattern space, 'P' is used to print up + to the newline (that is - the newly structured line) then 'D' + deletes the pattern space up to the newline, and starts a new + cycle. + + +File: sed.info-t, Node: tac, Next: cat -n, Prev: Line length adjustment, Up: Examples + +7.9 Reverse Lines of Files ========================== This one begins a series of totally useless (yet interesting) scripts -emulating various Unix commands. This, in particular, is a `tac' +emulating various Unix commands. This, in particular, is a 'tac' workalike. - Note that on implementations other than GNU `sed' this script might + Note that on implementations other than GNU 'sed' this script might easily overflow internal buffers. #!/usr/bin/sed -nf @@ -1542,18 +2893,18 @@ easily overflow internal buffers. h -File: sed.info, Node: cat -n, Next: cat -b, Prev: tac, Up: Examples +File: sed.info-t, Node: cat -n, Next: cat -b, Prev: tac, Up: Examples -4.7 Numbering Lines -=================== +7.10 Numbering Lines +==================== -This script replaces `cat -n'; in fact it formats its output exactly -like GNU `cat' does. +This script replaces 'cat -n'; in fact it formats its output exactly +like GNU 'cat' does. - Of course this is completely useless and for two reasons: first, + Of course this is completely useless and for two reasons: first, because somebody else did it in C, second, because the following -Bourne-shell script could be used for the same purpose and would be -much faster: +Bourne-shell script could be used for the same purpose and would be much +faster: #! /bin/sh sed -e "=" $@ | sed -e ' @@ -1562,16 +2913,16 @@ much faster: s/^ *\(......\)\n/\1 / ' - It uses `sed' to print the line number, then groups lines two by two -using `N'. Of course, this script does not teach as much as the one + It uses 'sed' to print the line number, then groups lines two by two +using 'N'. Of course, this script does not teach as much as the one presented below. - The algorithm used for incrementing uses both buffers, so the line -is printed as soon as possible and then discarded. The number is split -so that changing digits go in a buffer and unchanged ones go in the -other; the changed digits are modified in a single step (using a `y' -command). The line number for the next line is then composed and -stored in the hold space, to be used in the next iteration. + The algorithm used for incrementing uses both buffers, so the line is +printed as soon as possible and then discarded. The number is split so +that changing digits go in a buffer and unchanged ones go in the other; +the changed digits are modified in a single step (using a 'y' command). +The line number for the next line is then composed and stored in the +hold space, to be used in the next iteration. #!/usr/bin/sed -nf @@ -1611,16 +2962,16 @@ stored in the hold space, to be used in the next iteration. h -File: sed.info, Node: cat -b, Next: wc -c, Prev: cat -n, Up: Examples +File: sed.info-t, Node: cat -b, Next: wc -c, Prev: cat -n, Up: Examples -4.8 Numbering Non-blank Lines -============================= +7.11 Numbering Non-blank Lines +============================== -Emulating `cat -b' is almost the same as `cat -n'--we only have to +Emulating 'cat -b' is almost the same as 'cat -n'--we only have to select which lines are to be numbered and which are not. The part that is common to this script and the previous one is not -commented to show how important it is to comment `sed' scripts +commented to show how important it is to comment 'sed' scripts properly... #!/usr/bin/sed -nf @@ -1651,18 +3002,18 @@ properly... h -File: sed.info, Node: wc -c, Next: wc -w, Prev: cat -b, Up: Examples +File: sed.info-t, Node: wc -c, Next: wc -w, Prev: cat -b, Up: Examples -4.9 Counting Characters -======================= +7.12 Counting Characters +======================== -This script shows another way to do arithmetic with `sed'. In this -case we have to add possibly large numbers, so implementing this by +This script shows another way to do arithmetic with 'sed'. In this case +we have to add possibly large numbers, so implementing this by successive increments would not be feasible (and possibly even more complicated to contrive than this script). The approach is to map numbers to letters, kind of an abacus -implemented with `sed'. `a's are units, `b's are tens and so on: we +implemented with 'sed'. 'a's are units, 'b's are tens and so on: we simply add the number of characters on the current line as units, and then propagate the carry to tens, hundreds, and so on. @@ -1670,9 +3021,9 @@ then propagate the carry to tens, hundreds, and so on. On the last line, we convert the abacus form back to decimal. For the sake of variety, this is done with a loop rather than with some 80 -`s' commands(1): first we convert units, removing `a's from the number; -then we rotate letters so that tens become `a's, and so on until no -more letters remain. +'s' commands(1): first we convert units, removing 'a's from the number; +then we rotate letters so that tens become 'a's, and so on until no more +letters remain. #!/usr/bin/sed -nf @@ -1724,23 +3075,22 @@ more letters remain. (1) Some implementations have a limit of 199 commands per script -File: sed.info, Node: wc -w, Next: wc -l, Prev: wc -c, Up: Examples +File: sed.info-t, Node: wc -w, Next: wc -l, Prev: wc -c, Up: Examples -4.10 Counting Words +7.13 Counting Words =================== This script is almost the same as the previous one, once each of the -words on the line is converted to a single `a' (in the previous script -each letter was changed to an `a'). +words on the line is converted to a single 'a' (in the previous script +each letter was changed to an 'a'). - It is interesting that real `wc' programs have optimized loops for -`wc -c', so they are much slower at counting words rather than -characters. This script's bottleneck, instead, is arithmetic, and -hence the word-counting one is faster (it has to manage smaller -numbers). + It is interesting that real 'wc' programs have optimized loops for +'wc -c', so they are much slower at counting words rather than +characters. This script's bottleneck, instead, is arithmetic, and hence +the word-counting one is faster (it has to manage smaller numbers). Again, the common parts are not commented to show the importance of -commenting `sed' scripts. +commenting 'sed' scripts. #!/usr/bin/sed -nf @@ -1782,42 +3132,42 @@ commenting `sed' scripts. p -File: sed.info, Node: wc -l, Next: head, Prev: wc -w, Up: Examples +File: sed.info-t, Node: wc -l, Next: head, Prev: wc -w, Up: Examples -4.11 Counting Lines +7.14 Counting Lines =================== -No strange things are done now, because `sed' gives us `wc -l' -functionality for free!!! Look: +No strange things are done now, because 'sed' gives us 'wc -l' +functionality for free!!! Look: #!/usr/bin/sed -nf $= -File: sed.info, Node: head, Next: tail, Prev: wc -l, Up: Examples +File: sed.info-t, Node: head, Next: tail, Prev: wc -l, Up: Examples -4.12 Printing the First Lines +7.15 Printing the First Lines ============================= -This script is probably the simplest useful `sed' script. It displays +This script is probably the simplest useful 'sed' script. It displays the first 10 lines of input; the number of displayed lines is right -before the `q' command. +before the 'q' command. #!/usr/bin/sed -f 10q -File: sed.info, Node: tail, Next: uniq, Prev: head, Up: Examples +File: sed.info-t, Node: tail, Next: uniq, Prev: head, Up: Examples -4.13 Printing the Last Lines +7.16 Printing the Last Lines ============================ Printing the last N lines rather than the first is more complex but indeed possible. N is encoded in the second line, before the bang character. - This script is similar to the `tac' script in that it keeps the -final output in the hold space and prints it at the end: + This script is similar to the 'tac' script in that it keeps the final +output in the hold space and prints it at the end: #!/usr/bin/sed -nf @@ -1828,20 +3178,20 @@ final output in the hold space and prints it at the end: Mainly, the scripts keeps a window of 10 lines and slides it by adding a line and deleting the oldest (the substitution command on the -second line works like a `D' command but does not restart the loop). +second line works like a 'D' command but does not restart the loop). The "sliding window" technique is a very powerful way to write -efficient and complex `sed' scripts, because commands like `P' would +efficient and complex 'sed' scripts, because commands like 'P' would require a lot of work if implemented manually. To introduce the technique, which is fully demonstrated in the rest -of this chapter and is based on the `N', `P' and `D' commands, here is -an implementation of `tail' using a simple "sliding window." +of this chapter and is based on the 'N', 'P' and 'D' commands, here is +an implementation of 'tail' using a simple "sliding window." This looks complicated but in fact the working is the same as the last script: after we have kicked in the appropriate number of lines, however, we stop using the hold space to keep inter-line state, and -instead use `N' and `D' to slide pattern space by one line: +instead use 'N' and 'D' to slide pattern space by one line: #!/usr/bin/sed -f @@ -1858,12 +3208,12 @@ on the last line of input, appending the next input line to pattern space, and removing the first line. -File: sed.info, Node: uniq, Next: uniq -d, Prev: tail, Up: Examples +File: sed.info-t, Node: uniq, Next: uniq -d, Prev: tail, Up: Examples -4.14 Make Duplicate Lines Unique +7.17 Make Duplicate Lines Unique ================================ -This is an example of the art of using the `N', `P' and `D' commands, +This is an example of the art of using the 'N', 'P' and 'D' commands, probably the most difficult to master. #!/usr/bin/sed -f @@ -1880,7 +3230,7 @@ probably the most difficult to master. bb } - # If the `N' command had added the last line, print and exit + # If the N command had added the last line, print and exit $b # The lines are different; print the first and go @@ -1888,16 +3238,16 @@ probably the most difficult to master. P D - As you can see, we mantain a 2-line window using `P' and `D'. This -technique is often used in advanced `sed' scripts. + As you can see, we maintain a 2-line window using 'P' and 'D'. This +technique is often used in advanced 'sed' scripts. -File: sed.info, Node: uniq -d, Next: uniq -u, Prev: uniq, Up: Examples +File: sed.info-t, Node: uniq -d, Next: uniq -u, Prev: uniq, Up: Examples -4.15 Print Duplicated Lines of Input +7.18 Print Duplicated Lines of Input ==================================== -This script prints only duplicated lines, like `uniq -d'. +This script prints only duplicated lines, like 'uniq -d'. #!/usr/bin/sed -nf @@ -1926,12 +3276,12 @@ This script prints only duplicated lines, like `uniq -d'. D -File: sed.info, Node: uniq -u, Next: cat -s, Prev: uniq -d, Up: Examples +File: sed.info-t, Node: uniq -u, Next: cat -s, Prev: uniq -d, Up: Examples -4.16 Remove All Duplicated Lines +7.19 Remove All Duplicated Lines ================================ -This script prints only unique lines, like `uniq -u'. +This script prints only unique lines, like 'uniq -u'. #!/usr/bin/sed -f @@ -1948,7 +3298,7 @@ This script prints only unique lines, like `uniq -u'. # end of the file we simply exit $d - # Else, we keep reading lines with `N' until we + # Else, we keep reading lines with N until we # find a different one s/.*\n// N @@ -1961,14 +3311,14 @@ This script prints only unique lines, like `uniq -u'. D -File: sed.info, Node: cat -s, Prev: uniq -u, Up: Examples +File: sed.info-t, Node: cat -s, Prev: uniq -u, Up: Examples -4.17 Squeezing Blank Lines +7.20 Squeezing Blank Lines ========================== -As a final example, here are three scripts, of increasing complexity -and speed, that implement the same function as `cat -s', that is -squeezing blank lines. +As a final example, here are three scripts, of increasing complexity and +speed, that implement the same function as 'cat -s', that is squeezing +blank lines. The first leaves a blank line at the beginning and end if there are some already. @@ -2008,9 +3358,9 @@ beginning. It does leave a single blank line at end if one was there. } This removes leading and trailing blank lines. It is also the -fastest. Note that loops are completely done with `n' and `b', without -relying on `sed' to restart the the script automatically at the end of -a line. +fastest. Note that loops are completely done with 'n' and 'b', without +relying on 'sed' to restart the script automatically at the end of a +line. #!/usr/bin/sed -nf @@ -2042,17 +3392,17 @@ a line. bx -File: sed.info, Node: Limitations, Next: Other Resources, Prev: Examples, Up: Top +File: sed.info-t, Node: Limitations, Next: Other Resources, Prev: Examples, Up: Top -5 GNU `sed''s Limitations and Non-limitations +8 GNU 'sed''s Limitations and Non-limitations ********************************************* -For those who want to write portable `sed' scripts, be aware that some +For those who want to write portable 'sed' scripts, be aware that some implementations have been known to limit line lengths (for the pattern and hold spaces) to be no more than 4000 bytes. The POSIX standard -specifies that conforming `sed' implementations shall support at least -8192 byte line lengths. GNU `sed' has no built-in limit on line length; -as long as it can `malloc()' more (virtual) memory, you can feed or +specifies that conforming 'sed' implementations shall support at least +8192 byte line lengths. GNU 'sed' has no built-in limit on line length; +as long as it can 'malloc()' more (virtual) memory, you can feed or construct lines as long as you like. However, recursion is used to handle subpatterns and indefinite @@ -2060,553 +3410,1221 @@ repetition. This means that the available stack space may limit the size of the buffer that can be processed by certain patterns. -File: sed.info, Node: Other Resources, Next: Reporting Bugs, Prev: Limitations, Up: Top +File: sed.info-t, Node: Other Resources, Next: Reporting Bugs, Prev: Limitations, Up: Top -6 Other Resources for Learning About `sed' +9 Other Resources for Learning About 'sed' ****************************************** -In addition to several books that have been written about `sed' (either +In addition to several books that have been written about 'sed' (either specifically or as chapters in books which discuss shell programming), -one can find out more about `sed' (including suggestions of a few -books) from the FAQ for the `sed-users' mailing list, available from: - `http://sed.sourceforge.net/sedfaq.html' +one can find out more about 'sed' (including suggestions of a few books) +from the FAQ for the 'sed-users' mailing list, available from: + <http://sed.sourceforge.net/sedfaq.html> Also of interest are -`http://www.student.northpark.edu/pemente/sed/index.htm' and -`http://sed.sf.net/grabbag', which include `sed' tutorials and other -`sed'-related goodies. +<http://www.student.northpark.edu/pemente/sed/index.htm> and +<http://sed.sf.net/grabbag>, which include 'sed' tutorials and other +'sed'-related goodies. - The `sed-users' mailing list itself maintained by Sven Guckes. To -subscribe, visit `http://groups.yahoo.com' and search for the -`sed-users' mailing list. + The 'sed-users' mailing list itself maintained by Sven Guckes. To +subscribe, visit <http://groups.yahoo.com> and search for the +'sed-users' mailing list. -File: sed.info, Node: Reporting Bugs, Next: Extended regexps, Prev: Other Resources, Up: Top +File: sed.info-t, Node: Reporting Bugs, Next: GNU Free Documentation License, Prev: Other Resources, Up: Top -7 Reporting Bugs -**************** +10 Reporting Bugs +***************** -Email bug reports to <bug-sed@gnu.org>. Also, please include the -output of `sed --version' in the body of your report if at all possible. +Email bug reports to <bug-sed@gnu.org>. Also, please include the output +of 'sed --version' in the body of your report if at all possible. Please do not send a bug report like this: while building frobme-1.3.4 $ configure - error--> sed: file sedscr line 1: Unknown option to 's' + error-> sed: file sedscr line 1: Unknown option to 's' - If GNU `sed' doesn't configure your favorite package, take a few + If GNU 'sed' doesn't configure your favorite package, take a few extra minutes to identify the specific problem and make a stand-alone test case. Unlike other programs such as C compilers, making such test -cases for `sed' is quite simple. +cases for 'sed' is quite simple. A stand-alone test case includes all the data necessary to perform -the test, and the specific invocation of `sed' that causes the problem. +the test, and the specific invocation of 'sed' that causes the problem. The smaller a stand-alone test case is, the better. A test case should -not involve something as far removed from `sed' as "try to configure -frobme-1.3.4". Yes, that is in principle enough information to look -for the bug, but that is not a very practical prospect. +not involve something as far removed from 'sed' as "try to configure +frobme-1.3.4". Yes, that is in principle enough information to look for +the bug, but that is not a very practical prospect. Here are a few commonly reported bugs that are not bugs. -`N' command on the last line - Most versions of `sed' exit without printing anything when the `N' - command is issued on the last line of a file. GNU `sed' prints - pattern space before exiting unless of course the `-n' command +'N' command on the last line + + Most versions of 'sed' exit without printing anything when the 'N' + command is issued on the last line of a file. GNU 'sed' prints + pattern space before exiting unless of course the '-n' command switch has been specified. This choice is by design. + Default behavior (gnu extension, non-POSIX conforming): + $ seq 3 | sed N + 1 + 2 + 3 + To force POSIX-conforming behavior: + $ seq 3 | sed --posix N + 1 + 2 + For example, the behavior of sed N foo bar would depend on whether foo has an even or an odd number of lines(1). Or, when writing a script to read the next few lines - following a pattern match, traditional implementations of `sed' + following a pattern match, traditional implementations of 'sed' would force you to write something like /foo/{ $!N; $!N; $!N; $!N; $!N; $!N; $!N; $!N; $!N } instead of just /foo/{ N;N;N;N;N;N;N;N;N; } - In any case, the simplest workaround is to use `$d;N' in scripts + In any case, the simplest workaround is to use '$d;N' in scripts that rely on the traditional behavior, or to set the - `POSIXLY_CORRECT' variable to a non-empty value. + 'POSIXLY_CORRECT' variable to a non-empty value. Regex syntax clashes (problems with backslashes) - `sed' uses the POSIX basic regular expression syntax. According to + 'sed' uses the POSIX basic regular expression syntax. According to the standard, the meaning of some escape sequences is undefined in - this syntax; notable in the case of `sed' are `\|', `\+', `\?', - `\`', `\'', `\<', `\>', `\b', `\B', `\w', and `\W'. + this syntax; notable in the case of 'sed' are '\|', '\+', '\?', + '\`', '\'', '\<', '\>', '\b', '\B', '\w', and '\W'. As in all GNU programs that use POSIX basic regular expressions, - `sed' interprets these escape sequences as special characters. - So, `x\+' matches one or more occurrences of `x'. `abc\|def' - matches either `abc' or `def'. + 'sed' interprets these escape sequences as special characters. So, + 'x\+' matches one or more occurrences of 'x'. 'abc\|def' matches + either 'abc' or 'def'. This syntax may cause problems when running scripts written for - other `sed's. Some `sed' programs have been written with the - assumption that `\|' and `\+' match the literal characters `|' and - `+'. Such scripts must be modified by removing the spurious + other 'sed's. Some 'sed' programs have been written with the + assumption that '\|' and '\+' match the literal characters '|' and + '+'. Such scripts must be modified by removing the spurious backslashes if they are to be used with modern implementations of - `sed', like GNU `sed'. + 'sed', like GNU 'sed'. On the other hand, some scripts use s|abc\|def||g to remove - occurrences of _either_ `abc' or `def'. While this worked until - `sed' 4.0.x, newer versions interpret this as removing the string - `abc|def'. This is again undefined behavior according to POSIX, - and this interpretation is arguably more robust: older `sed's, for - example, required that the regex matcher parsed `\/' as `/' in the - common case of escaping a slash, which is again undefined - behavior; the new behavior avoids this, and this is good because - the regex matcher is only partially under our control. - - In addition, this version of `sed' supports several escape + occurrences of _either_ 'abc' or 'def'. While this worked until + 'sed' 4.0.x, newer versions interpret this as removing the string + 'abc|def'. This is again undefined behavior according to POSIX, + and this interpretation is arguably more robust: older 'sed's, for + example, required that the regex matcher parsed '\/' as '/' in the + common case of escaping a slash, which is again undefined behavior; + the new behavior avoids this, and this is good because the regex + matcher is only partially under our control. + + In addition, this version of 'sed' supports several escape characters (some of which are multi-character) to insert - non-printable characters in scripts (`\a', `\c', `\d', `\o', `\r', - `\t', `\v', `\x'). These can cause similar problems with scripts - written for other `sed's. + non-printable characters in scripts ('\a', '\c', '\d', '\o', '\r', + '\t', '\v', '\x'). These can cause similar problems with scripts + written for other 'sed's. -`-i' clobbers read-only files - In short, `sed -i' will let you delete the contents of a read-only - file, and in general the `-i' option (*note Invocation: Invoking +'-i' clobbers read-only files + + In short, 'sed -i' will let you delete the contents of a read-only + file, and in general the '-i' option (*note Invocation: Invoking sed.) lets you clobber protected files. This is not a bug, but - rather a consequence of how the Unix filesystem works. + rather a consequence of how the Unix file system works. The permissions on a file say what can happen to the data in that file, while the permissions on a directory say what can happen to - the list of files in that directory. `sed -i' will not ever open - for writing a file that is already on disk. Rather, it will work + the list of files in that directory. 'sed -i' will not ever open + for writing a file that is already on disk. Rather, it will work on a temporary file that is finally renamed to the original name: if you rename or delete files, you're actually modifying the contents of the directory, so the operation depends on the permissions of the directory, not of the file. For this same - reason, `sed' does not let you use `-i' on a writeable file in a + reason, 'sed' does not let you use '-i' on a writable file in a read-only directory, and will break hard or symbolic links when - `-i' is used on such a file. + '-i' is used on such a file. + +'0a' does not work (gives an error) -`0a' does not work (gives an error) There is no line 0. 0 is a special address that is only used to - treat addresses like `0,/RE/' as active when the script starts: if - you write `1,/abc/d' and the first line includes the word `abc', + treat addresses like '0,/RE/' as active when the script starts: if + you write '1,/abc/d' and the first line includes the word 'abc', then that match would be ignored because address ranges must span at least two lines (barring the end of the file); but what you probably wanted is to delete every line up to the first one - including `abc', and this is obtained with `0,/abc/d'. + including 'abc', and this is obtained with '0,/abc/d'. + +'[a-z]' is case insensitive -`[a-z]' is case insensitive You are encountering problems with locales. POSIX mandates that - `[a-z]' uses the current locale's collation order - in C parlance, - that means using `strcoll(3)' instead of `strcmp(3)'. Some - locales have a case-insensitive collation order, others don't. + '[a-z]' uses the current locale's collation order - in C parlance, + that means using 'strcoll(3)' instead of 'strcmp(3)'. Some locales + have a case-insensitive collation order, others don't. - Another problem is that `[a-z]' tries to use collation symbols. + Another problem is that '[a-z]' tries to use collation symbols. This only happens if you are on the GNU system, using GNU libc's regular expression matcher instead of compiling the one supplied with GNU sed. In a Danish locale, for example, the regular - expression `^[a-z]$' matches the string `aa', because this is a - single collating symbol that comes after `a' and before `b'; `ll' - behaves similarly in Spanish locales, or `ij' in Dutch locales. + expression '^[a-z]$' matches the string 'aa', because this is a + single collating symbol that comes after 'a' and before 'b'; 'll' + behaves similarly in Spanish locales, or 'ij' in Dutch locales. To work around these problems, which may cause bugs in shell - scripts, set the `LC_COLLATE' and `LC_CTYPE' environment variables - to `C'. + scripts, set the 'LC_COLLATE' and 'LC_CTYPE' environment variables + to 'C'. + +'s/.*//' does not clear pattern space -`s/.*//' does not clear pattern space This happens if your input stream includes invalid multibyte - sequences. POSIX mandates that such sequences are _not_ matched - by `.', so that `s/.*//' will not clear pattern space as you would + sequences. POSIX mandates that such sequences are _not_ matched by + '.', so that 's/.*//' will not clear pattern space as you would expect. In fact, there is no way to clear sed's buffers in the middle of the script in most multibyte locales (including UTF-8 - locales). For this reason, GNU `sed' provides a `z' command (for - `zap') as an extension. + locales). For this reason, GNU 'sed' provides a 'z' command (for + 'zap') as an extension. To work around these problems, which may cause bugs in shell - scripts, set the `LC_COLLATE' and `LC_CTYPE' environment variables - to `C'. + scripts, set the 'LC_COLLATE' and 'LC_CTYPE' environment variables + to 'C'. ---------- Footnotes ---------- (1) which is the actual "bug" that prompted the change in behavior -File: sed.info, Node: Extended regexps, Next: Concept Index, Prev: Reporting Bugs, Up: Top - -Appendix A Extended regular expressions -*************************************** - -The only difference between basic and extended regular expressions is in -the behavior of a few characters: `?', `+', parentheses, braces (`{}'), -and `|'. While basic regular expressions require these to be escaped -if you want them to behave as special characters, when using extended -regular expressions you must escape them if you want them _to match a -literal character_. `|' is special here because `\|' is a GNU -extension - standard basic regular expressions do not provide its -functionality. - -Examples: -`abc?' - becomes `abc\?' when using extended regular expressions. It - matches the literal string `abc?'. - -`c\+' - becomes `c+' when using extended regular expressions. It matches - one or more `c's. - -`a\{3,\}' - becomes `a{3,}' when using extended regular expressions. It - matches three or more `a's. - -`\(abc\)\{2,3\}' - becomes `(abc){2,3}' when using extended regular expressions. It - matches either `abcabc' or `abcabcabc'. - -`\(abc*\)\1' - becomes `(abc*)\1' when using extended regular expressions. - Backreferences must still be escaped when using extended regular - expressions. +File: sed.info-t, Node: GNU Free Documentation License, Next: Concept Index, Prev: Reporting Bugs, Up: Top + +Appendix A GNU Free Documentation License +***************************************** + + Version 1.3, 3 November 2008 + + Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. + <http://fsf.org/> + + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + 0. PREAMBLE + + The purpose of this License is to make a manual, textbook, or other + functional and useful document "free" in the sense of freedom: to + assure everyone the effective freedom to copy and redistribute it, + with or without modifying it, either commercially or + noncommercially. Secondarily, this License preserves for the + author and publisher a way to get credit for their work, while not + being considered responsible for modifications made by others. + + This License is a kind of "copyleft", which means that derivative + works of the document must themselves be free in the same sense. + It complements the GNU General Public License, which is a copyleft + license designed for free software. + + We have designed this License in order to use it for manuals for + free software, because free software needs free documentation: a + free program should come with manuals providing the same freedoms + that the software does. But this License is not limited to + software manuals; it can be used for any textual work, regardless + of subject matter or whether it is published as a printed book. We + recommend this License principally for works whose purpose is + instruction or reference. + + 1. 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AGGREGATION WITH INDEPENDENT WORKS + + A compilation of the Document or its derivatives with other + separate and independent documents or works, in or on a volume of a + storage or distribution medium, is called an "aggregate" if the + copyright resulting from the compilation is not used to limit the + legal rights of the compilation's users beyond what the individual + works permit. When the Document is included in an aggregate, this + License does not apply to the other works in the aggregate which + are not themselves derivative works of the Document. + + If the Cover Text requirement of section 3 is applicable to these + copies of the Document, then if the Document is less than one half + of the entire aggregate, the Document's Cover Texts may be placed + on covers that bracket the Document within the aggregate, or the + electronic equivalent of covers if the Document is in electronic + form. Otherwise they must appear on printed covers that bracket + the whole aggregate. + + 8. TRANSLATION + + Translation is considered a kind of modification, so you may + distribute translations of the Document under the terms of section + 4. Replacing Invariant Sections with translations requires special + permission from their copyright holders, but you may include + translations of some or all Invariant Sections in addition to the + original versions of these Invariant Sections. You may include a + translation of this License, and all the license notices in the + Document, and any Warranty Disclaimers, provided that you also + include the original English version of this License and the + original versions of those notices and disclaimers. In case of a + disagreement between the translation and the original version of + this License or a notice or disclaimer, the original version will + prevail. + + If a section in the Document is Entitled "Acknowledgements", + "Dedications", or "History", the requirement (section 4) to + Preserve its Title (section 1) will typically require changing the + actual title. + + 9. TERMINATION + + You may not copy, modify, sublicense, or distribute the Document + except as expressly provided under this License. Any attempt + otherwise to copy, modify, sublicense, or distribute it is void, + and will automatically terminate your rights under this License. + + However, if you cease all violation of this License, then your + license from a particular copyright holder is reinstated (a) + provisionally, unless and until the copyright holder explicitly and + finally terminates your license, and (b) permanently, if the + copyright holder fails to notify you of the violation by some + reasonable means prior to 60 days after the cessation. + + Moreover, your license from a particular copyright holder is + reinstated permanently if the copyright holder notifies you of the + violation by some reasonable means, this is the first time you have + received notice of violation of this License (for any work) from + that copyright holder, and you cure the violation prior to 30 days + after your receipt of the notice. + + Termination of your rights under this section does not terminate + the licenses of parties who have received copies or rights from you + under this License. If your rights have been terminated and not + permanently reinstated, receipt of a copy of some or all of the + same material does not give you any rights to use it. + + 10. FUTURE REVISIONS OF THIS LICENSE + + The Free Software Foundation may publish new, revised versions of + the GNU Free Documentation License from time to time. Such new + versions will be similar in spirit to the present version, but may + differ in detail to address new problems or concerns. See + <http://www.gnu.org/copyleft/>. + + Each version of the License is given a distinguishing version + number. If the Document specifies that a particular numbered + version of this License "or any later version" applies to it, you + have the option of following the terms and conditions either of + that specified version or of any later version that has been + published (not as a draft) by the Free Software Foundation. If the + Document does not specify a version number of this License, you may + choose any version ever published (not as a draft) by the Free + Software Foundation. If the Document specifies that a proxy can + decide which future versions of this License can be used, that + proxy's public statement of acceptance of a version permanently + authorizes you to choose that version for the Document. + + 11. RELICENSING + + "Massive Multiauthor Collaboration Site" (or "MMC Site") means any + World Wide Web server that publishes copyrightable works and also + provides prominent facilities for anybody to edit those works. A + public wiki that anybody can edit is an example of such a server. + A "Massive Multiauthor Collaboration" (or "MMC") contained in the + site means any set of copyrightable works thus published on the MMC + site. + + "CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0 + license published by Creative Commons Corporation, a not-for-profit + corporation with a principal place of business in San Francisco, + California, as well as future copyleft versions of that license + published by that same organization. + + "Incorporate" means to publish or republish a Document, in whole or + in part, as part of another Document. + + An MMC is "eligible for relicensing" if it is licensed under this + License, and if all works that were first published under this + License somewhere other than this MMC, and subsequently + incorporated in whole or in part into the MMC, (1) had no cover + texts or invariant sections, and (2) were thus incorporated prior + to November 1, 2008. + + The operator of an MMC Site may republish an MMC contained in the + site under CC-BY-SA on the same site at any time before August 1, + 2009, provided the MMC is eligible for relicensing. + +ADDENDUM: How to use this License for your documents +==================================================== + +To use this License in a document you have written, include a copy of +the License in the document and put the following copyright and license +notices just after the title page: + + Copyright (C) YEAR YOUR NAME. + Permission is granted to copy, distribute and/or modify this document + under the terms of the GNU Free Documentation License, Version 1.3 + or any later version published by the Free Software Foundation; + with no Invariant Sections, no Front-Cover Texts, and no Back-Cover + Texts. A copy of the license is included in the section entitled ``GNU + Free Documentation License''. + + If you have Invariant Sections, Front-Cover Texts and Back-Cover +Texts, replace the "with...Texts." line with this: + + with the Invariant Sections being LIST THEIR TITLES, with + the Front-Cover Texts being LIST, and with the Back-Cover Texts + being LIST. + + If you have Invariant Sections without Cover Texts, or some other +combination of the three, merge those two alternatives to suit the +situation. + + If your document contains nontrivial examples of program code, we +recommend releasing these examples in parallel under your choice of free +software license, such as the GNU General Public License, to permit +their use in free software. -File: sed.info, Node: Concept Index, Next: Command and Option Index, Prev: Extended regexps, Up: Top +File: sed.info-t, Node: Concept Index, Next: Command and Option Index, Prev: GNU Free Documentation License, Up: Top Concept Index ************* This is a general index of all issues discussed in this manual, with the -exception of the `sed' commands and command-line options. +exception of the 'sed' commands and command-line options. * Menu: -* 0 address: Reporting Bugs. (line 102) +* -e, example: Overview. (line 43) +* -e, example <1>: sed script overview. (line 37) +* -expression, example: Overview. (line 43) +* -f, example: Overview. (line 43) +* -f, example <1>: sed script overview. (line 37) +* -file, example: Overview. (line 43) +* -i, example: Overview. (line 23) +* -n, example: Overview. (line 30) +* -s, example: Overview. (line 37) +* 0 address: Reporting Bugs. (line 114) +* ;, command separator: sed script overview. (line 37) +* a, and semicolons: sed script overview. (line 56) * Additional reading about sed: Other Resources. (line 6) -* ADDR1,+N: Addresses. (line 80) -* ADDR1,~N: Addresses. (line 80) -* Address, as a regular expression: Addresses. (line 27) -* Address, last line: Addresses. (line 22) -* Address, numeric: Addresses. (line 8) -* Addresses, in sed scripts: Addresses. (line 6) -* Append hold space to pattern space: Other Commands. (line 125) -* Append next input line to pattern space: Other Commands. (line 105) -* Append pattern space to hold space: Other Commands. (line 117) -* Appending text after a line: Other Commands. (line 27) -* Backreferences, in regular expressions: The "s" Command. (line 19) -* Branch to a label, if s/// failed: Extended Commands. (line 71) +* ADDR1,+N: Range Addresses. (line 31) +* ADDR1,~N: Range Addresses. (line 31) +* address range, example: sed script overview. (line 23) +* Address, as a regular expression: Regexp Addresses. (line 13) +* Address, last line: Numeric Addresses. (line 13) +* Address, numeric: Numeric Addresses. (line 8) +* addresses, excluding: Addresses overview. (line 31) +* Addresses, in sed scripts: Numeric Addresses. (line 6) +* addresses, negating: Addresses overview. (line 31) +* addresses, numeric: Addresses overview. (line 6) +* addresses, range: Addresses overview. (line 24) +* addresses, regular expression: Addresses overview. (line 18) +* addresses, syntax: sed script overview. (line 13) +* alphabetic characters: Character Classes and Bracket Expressions. + (line 49) +* alphanumeric characters: Character Classes and Bracket Expressions. + (line 44) +* Append hold space to pattern space: Other Commands. (line 284) +* Append next input line to pattern space: Other Commands. (line 257) +* Append pattern space to hold space: Other Commands. (line 276) +* Appending text after a line: Other Commands. (line 45) +* back-reference: Back-references and Subexpressions. + (line 6) +* Backreferences, in regular expressions: The "s" Command. (line 18) +* blank characters: Character Classes and Bracket Expressions. + (line 54) +* bracket expression: Character Classes and Bracket Expressions. + (line 6) +* Branch to a label, if s/// failed: Extended Commands. (line 63) * Branch to a label, if s/// succeeded: Programming Commands. (line 22) * Branch to a label, unconditionally: Programming Commands. (line 18) * Buffer spaces, pattern and hold: Execution Cycle. (line 6) * Bugs, reporting: Reporting Bugs. (line 6) -* Case-insensitive matching: The "s" Command. (line 112) +* c, and semicolons: sed script overview. (line 56) +* case insensitive, regular expression: Regexp Addresses. (line 47) +* Case-insensitive matching: The "s" Command. (line 117) * Caveat -- #n on first line: Common Commands. (line 20) -* Command groups: Common Commands. (line 50) +* character class: Character Classes and Bracket Expressions. + (line 6) +* character classes: Character Classes and Bracket Expressions. + (line 43) +* classes of characters: Character Classes and Bracket Expressions. + (line 43) +* Command groups: Common Commands. (line 91) * Comments, in scripts: Common Commands. (line 12) -* Conditional branch <1>: Extended Commands. (line 71) * Conditional branch: Programming Commands. (line 22) -* Copy hold space into pattern space: Other Commands. (line 121) -* Copy pattern space into hold space: Other Commands. (line 113) -* Delete first line from pattern space: Other Commands. (line 99) -* Disabling autoprint, from command line: Invoking sed. (line 34) -* empty regular expression: Addresses. (line 31) -* Emptying pattern space <1>: Reporting Bugs. (line 129) -* Emptying pattern space: Extended Commands. (line 93) +* Conditional branch <1>: Extended Commands. (line 63) +* control characters: Character Classes and Bracket Expressions. + (line 57) +* Copy hold space into pattern space: Other Commands. (line 280) +* Copy pattern space into hold space: Other Commands. (line 272) +* d, example: sed script overview. (line 23) +* Delete first line from pattern space: Other Commands. (line 251) +* digit characters: Character Classes and Bracket Expressions. + (line 62) +* Disabling autoprint, from command line: Command-Line Options. + (line 23) +* empty regular expression: Regexp Addresses. (line 22) +* Emptying pattern space: Extended Commands. (line 85) +* Emptying pattern space <1>: Reporting Bugs. (line 143) * Evaluate Bourne-shell commands: Extended Commands. (line 12) * Evaluate Bourne-shell commands, after substitution: The "s" Command. - (line 103) -* Exchange hold space with pattern space: Other Commands. (line 129) -* Excluding lines: Addresses. (line 103) -* Extended regular expressions, choosing: Invoking sed. (line 113) -* Extended regular expressions, syntax: Extended regexps. (line 6) + (line 108) +* example, address range: sed script overview. (line 23) +* example, regular expression: sed script overview. (line 28) +* Exchange hold space with pattern space: Other Commands. (line 288) +* Excluding lines: Addresses overview. (line 31) +* exit status: Exit status. (line 6) +* exit status, example: Exit status. (line 25) +* Extended regular expressions, choosing: Command-Line Options. + (line 102) +* Extended regular expressions, syntax: ERE syntax. (line 6) * File name, printing: Extended Commands. (line 30) -* Files to be processed as input: Invoking sed. (line 148) +* Files to be processed as input: Command-Line Options. + (line 148) * Flow of control in scripts: Programming Commands. (line 11) -* Global substitution: The "s" Command. (line 69) -* GNU extensions, /dev/stderr file <1>: Other Commands. (line 88) -* GNU extensions, /dev/stderr file: The "s" Command. (line 96) -* GNU extensions, /dev/stdin file <1>: Extended Commands. (line 61) -* GNU extensions, /dev/stdin file: Other Commands. (line 78) -* GNU extensions, /dev/stdout file <1>: Other Commands. (line 88) -* GNU extensions, /dev/stdout file <2>: The "s" Command. (line 96) -* GNU extensions, /dev/stdout file: Invoking sed. (line 156) -* GNU extensions, 0 address <1>: Reporting Bugs. (line 102) -* GNU extensions, 0 address: Addresses. (line 80) -* GNU extensions, 0,ADDR2 addressing: Addresses. (line 80) -* GNU extensions, ADDR1,+N addressing: Addresses. (line 80) -* GNU extensions, ADDR1,~N addressing: Addresses. (line 80) -* GNU extensions, branch if s/// failed: Extended Commands. (line 71) +* Global substitution: The "s" Command. (line 74) +* GNU extensions, /dev/stderr file: The "s" Command. (line 101) +* GNU extensions, /dev/stderr file <1>: Other Commands. (line 240) +* GNU extensions, /dev/stdin file: Other Commands. (line 227) +* GNU extensions, /dev/stdin file <1>: Extended Commands. (line 53) +* GNU extensions, /dev/stdout file: Command-Line Options. + (line 156) +* GNU extensions, /dev/stdout file <1>: The "s" Command. (line 101) +* GNU extensions, /dev/stdout file <2>: Other Commands. (line 240) +* GNU extensions, 0 address: Range Addresses. (line 31) +* GNU extensions, 0 address <1>: Reporting Bugs. (line 114) +* GNU extensions, 0,ADDR2 addressing: Range Addresses. (line 31) +* GNU extensions, ADDR1,+N addressing: Range Addresses. (line 31) +* GNU extensions, ADDR1,~N addressing: Range Addresses. (line 31) +* GNU extensions, branch if s/// failed: Extended Commands. (line 63) * GNU extensions, case modifiers in s commands: The "s" Command. - (line 23) + (line 29) * GNU extensions, checking for their presence: Extended Commands. - (line 77) -* GNU extensions, disabling: Invoking sed. (line 81) -* GNU extensions, emptying pattern space <1>: Reporting Bugs. (line 129) -* GNU extensions, emptying pattern space: Extended Commands. (line 93) + (line 69) +* GNU extensions, disabling: Command-Line Options. + (line 69) +* GNU extensions, emptying pattern space: Extended Commands. (line 85) +* GNU extensions, emptying pattern space <1>: Reporting Bugs. (line 143) +* GNU extensions, evaluating Bourne-shell commands: The "s" Command. + (line 108) * GNU extensions, evaluating Bourne-shell commands <1>: Extended Commands. (line 12) -* GNU extensions, evaluating Bourne-shell commands: The "s" Command. - (line 103) -* GNU extensions, extended regular expressions: Invoking sed. (line 113) -* GNU extensions, g and NUMBER modifier interaction in s command: The "s" Command. - (line 75) -* GNU extensions, I modifier <1>: The "s" Command. (line 112) -* GNU extensions, I modifier: Addresses. (line 49) -* GNU extensions, in-place editing <1>: Reporting Bugs. (line 84) -* GNU extensions, in-place editing: Invoking sed. (line 51) -* GNU extensions, L command: Extended Commands. (line 34) -* GNU extensions, M modifier <1>: The "s" Command. (line 117) -* GNU extensions, M modifier: Addresses. (line 54) -* GNU extensions, modifiers and the empty regular expression: Addresses. - (line 31) -* GNU extensions, N~M addresses: Addresses. (line 13) -* GNU extensions, quitting silently: Extended Commands. (line 44) -* GNU extensions, R command: Extended Commands. (line 61) +* GNU extensions, extended regular expressions: Command-Line Options. + (line 102) +* GNU extensions, g and NUMBER modifier: The "s" Command. (line 80) +* GNU extensions, I modifier: The "s" Command. (line 117) +* GNU extensions, I modifier <1>: Regexp Addresses. (line 47) +* GNU extensions, in-place editing: Command-Line Options. + (line 40) +* GNU extensions, in-place editing <1>: Reporting Bugs. (line 95) +* GNU extensions, M modifier: The "s" Command. (line 122) +* GNU extensions, M modifier <1>: Regexp Addresses. (line 75) +* GNU extensions, modifiers and the empty regular expression: Regexp Addresses. + (line 22) +* GNU extensions, N~M addresses: Numeric Addresses. (line 18) +* GNU extensions, quitting silently: Extended Commands. (line 36) +* GNU extensions, R command: Extended Commands. (line 53) * GNU extensions, reading a file a line at a time: Extended Commands. - (line 61) -* GNU extensions, reformatting paragraphs: Extended Commands. (line 34) + (line 53) +* GNU extensions, returning an exit code: Common Commands. (line 28) * GNU extensions, returning an exit code <1>: Extended Commands. - (line 44) -* GNU extensions, returning an exit code: Common Commands. (line 30) -* GNU extensions, setting line length: Other Commands. (line 65) -* GNU extensions, special escapes <1>: Reporting Bugs. (line 77) + (line 36) +* GNU extensions, setting line length: Other Commands. (line 207) * GNU extensions, special escapes: Escapes. (line 6) -* GNU extensions, special two-address forms: Addresses. (line 80) +* GNU extensions, special escapes <1>: Reporting Bugs. (line 88) +* GNU extensions, special two-address forms: Range Addresses. (line 31) +* GNU extensions, subprocesses: The "s" Command. (line 108) * GNU extensions, subprocesses <1>: Extended Commands. (line 12) -* GNU extensions, subprocesses: The "s" Command. (line 103) -* GNU extensions, to basic regular expressions <1>: Reporting Bugs. - (line 50) -* GNU extensions, to basic regular expressions: Regular Expressions. - (line 26) +* GNU extensions, to basic regular expressions: BRE syntax. (line 13) +* GNU extensions, to basic regular expressions <1>: BRE syntax. + (line 59) +* GNU extensions, to basic regular expressions <2>: BRE syntax. + (line 62) +* GNU extensions, to basic regular expressions <3>: BRE syntax. + (line 77) +* GNU extensions, to basic regular expressions <4>: BRE syntax. + (line 87) +* GNU extensions, to basic regular expressions <5>: Reporting Bugs. + (line 61) * GNU extensions, two addresses supported by most commands: Other Commands. - (line 25) + (line 61) +* GNU extensions, two addresses supported by most commands <1>: Other Commands. + (line 115) +* GNU extensions, two addresses supported by most commands <2>: Other Commands. + (line 204) +* GNU extensions, two addresses supported by most commands <3>: Other Commands. + (line 236) * GNU extensions, unlimited line length: Limitations. (line 6) * GNU extensions, writing first line to a file: Extended Commands. - (line 88) + (line 80) * Goto, in scripts: Programming Commands. (line 18) -* Greedy regular expression matching: Regular Expressions. (line 143) -* Grouping commands: Common Commands. (line 50) -* Hold space, appending from pattern space: Other Commands. (line 117) -* Hold space, appending to pattern space: Other Commands. (line 125) -* Hold space, copy into pattern space: Other Commands. (line 121) -* Hold space, copying pattern space into: Other Commands. (line 113) +* graphic characters: Character Classes and Bracket Expressions. + (line 65) +* Greedy regular expression matching: BRE syntax. (line 113) +* Grouping commands: Common Commands. (line 91) +* hexadecimal digits: Character Classes and Bracket Expressions. + (line 88) +* Hold space, appending from pattern space: Other Commands. (line 276) +* Hold space, appending to pattern space: Other Commands. (line 284) +* Hold space, copy into pattern space: Other Commands. (line 280) +* Hold space, copying pattern space into: Other Commands. (line 272) * Hold space, definition: Execution Cycle. (line 6) -* Hold space, exchange with pattern space: Other Commands. (line 129) -* In-place editing: Reporting Bugs. (line 84) -* In-place editing, activating: Invoking sed. (line 51) -* In-place editing, Perl-style backup file names: Invoking sed. - (line 62) -* Inserting text before a line: Other Commands. (line 46) +* Hold space, exchange with pattern space: Other Commands. (line 288) +* i, and semicolons: sed script overview. (line 56) +* In-place editing: Reporting Bugs. (line 95) +* In-place editing, activating: Command-Line Options. + (line 40) +* In-place editing, Perl-style backup file names: Command-Line Options. + (line 51) +* Inserting text before a line: Other Commands. (line 104) * Labels, in scripts: Programming Commands. (line 14) -* Last line, selecting: Addresses. (line 22) -* Line length, setting <1>: Other Commands. (line 65) -* Line length, setting: Invoking sed. (line 76) -* Line number, printing: Other Commands. (line 62) -* Line selection: Addresses. (line 6) -* Line, selecting by number: Addresses. (line 8) -* Line, selecting by regular expression match: Addresses. (line 27) -* Line, selecting last: Addresses. (line 22) -* List pattern space: Other Commands. (line 65) +* Last line, selecting: Numeric Addresses. (line 13) +* Line length, setting: Command-Line Options. + (line 64) +* Line length, setting <1>: Other Commands. (line 207) +* Line number, printing: Other Commands. (line 194) +* Line selection: Numeric Addresses. (line 6) +* Line, selecting by number: Numeric Addresses. (line 8) +* Line, selecting by regular expression match: Regexp Addresses. + (line 13) +* Line, selecting last: Numeric Addresses. (line 13) +* List pattern space: Other Commands. (line 207) +* lower-case letters: Character Classes and Bracket Expressions. + (line 68) * Mixing g and NUMBER modifiers in the s command: The "s" Command. - (line 75) -* Next input line, append to pattern space: Other Commands. (line 105) + (line 80) +* multiple files: Overview. (line 37) +* multiple sed commands: sed script overview. (line 37) +* named character classes: Character Classes and Bracket Expressions. + (line 43) +* newline, command separator: sed script overview. (line 37) +* Next input line, append to pattern space: Other Commands. (line 257) * Next input line, replace pattern space with: Common Commands. - (line 44) -* Non-bugs, 0 address: Reporting Bugs. (line 102) -* Non-bugs, in-place editing: Reporting Bugs. (line 84) -* Non-bugs, localization-related: Reporting Bugs. (line 111) + (line 61) +* Non-bugs, 0 address: Reporting Bugs. (line 114) +* Non-bugs, in-place editing: Reporting Bugs. (line 95) +* Non-bugs, localization-related: Reporting Bugs. (line 124) +* Non-bugs, localization-related <1>: Reporting Bugs. (line 143) * Non-bugs, N command on the last line: Reporting Bugs. (line 30) -* Non-bugs, regex syntax clashes: Reporting Bugs. (line 50) -* Parenthesized substrings: The "s" Command. (line 19) +* Non-bugs, regex syntax clashes: Reporting Bugs. (line 61) +* numeric addresses: Addresses overview. (line 6) +* numeric characters: Character Classes and Bracket Expressions. + (line 62) +* output: Overview. (line 23) +* output, suppressing: Overview. (line 30) +* p, example: Overview. (line 30) +* paragraphs, processing: Multiline techniques. + (line 53) +* parameters, script: Overview. (line 43) +* Parenthesized substrings: The "s" Command. (line 18) * Pattern space, definition: Execution Cycle. (line 6) * Portability, comments: Common Commands. (line 15) * Portability, line length limitations: Limitations. (line 6) * Portability, N command on the last line: Reporting Bugs. (line 30) -* POSIXLY_CORRECT behavior, bracket expressions: Regular Expressions. - (line 105) -* POSIXLY_CORRECT behavior, enabling: Invoking sed. (line 84) +* POSIXLY_CORRECT behavior, bracket expressions: Character Classes and Bracket Expressions. + (line 112) +* POSIXLY_CORRECT behavior, enabling: Command-Line Options. + (line 72) * POSIXLY_CORRECT behavior, escapes: Escapes. (line 11) -* POSIXLY_CORRECT behavior, N command: Reporting Bugs. (line 45) -* Print first line from pattern space: Other Commands. (line 110) +* POSIXLY_CORRECT behavior, N command: Reporting Bugs. (line 56) +* Print first line from pattern space: Other Commands. (line 269) +* printable characters: Character Classes and Bracket Expressions. + (line 72) * Printing file name: Extended Commands. (line 30) -* Printing line number: Other Commands. (line 62) -* Printing text unambiguously: Other Commands. (line 65) -* Quitting <1>: Extended Commands. (line 44) -* Quitting: Common Commands. (line 30) -* Range of lines: Addresses. (line 67) -* Range with start address of zero: Addresses. (line 80) -* Read next input line: Common Commands. (line 44) -* Read text from a file <1>: Extended Commands. (line 61) -* Read text from a file: Other Commands. (line 78) -* Reformat pattern space: Extended Commands. (line 34) -* Reformatting paragraphs: Extended Commands. (line 34) +* Printing line number: Other Commands. (line 194) +* Printing text unambiguously: Other Commands. (line 207) +* processing paragraphs: Multiline techniques. + (line 53) +* punctuation characters: Character Classes and Bracket Expressions. + (line 75) +* Q, example: Exit status. (line 25) +* q, example: sed script overview. (line 28) +* Quitting: Common Commands. (line 28) +* Quitting <1>: Extended Commands. (line 36) +* range addresses: Addresses overview. (line 24) +* range expression: Character Classes and Bracket Expressions. + (line 18) +* Range of lines: Range Addresses. (line 6) +* Range with start address of zero: Range Addresses. (line 31) +* Read next input line: Common Commands. (line 61) +* Read text from a file: Other Commands. (line 219) +* Read text from a file <1>: Extended Commands. (line 53) +* regular expression addresses: Addresses overview. (line 18) +* regular expression, example: sed script overview. (line 28) * Replace hold space with copy of pattern space: Other Commands. - (line 113) + (line 272) * Replace pattern space with copy of hold space: Other Commands. - (line 121) + (line 280) * Replacing all text matching regexp in a line: The "s" Command. - (line 69) + (line 74) * Replacing only Nth match of regexp in a line: The "s" Command. - (line 73) -* Replacing selected lines with other text: Other Commands. (line 52) -* Requiring GNU sed: Extended Commands. (line 77) -* Script structure: sed Programs. (line 6) -* Script, from a file: Invoking sed. (line 46) -* Script, from command line: Invoking sed. (line 41) -* sed program structure: sed Programs. (line 6) -* Selecting lines to process: Addresses. (line 6) -* Selecting non-matching lines: Addresses. (line 103) -* Several lines, selecting: Addresses. (line 67) -* Slash character, in regular expressions: Addresses. (line 41) + (line 78) +* Replacing selected lines with other text: Other Commands. (line 157) +* Requiring GNU sed: Extended Commands. (line 69) +* Sandbox mode: Command-Line Options. + (line 124) +* script parameter: Overview. (line 43) +* Script structure: sed script overview. (line 6) +* Script, from a file: Command-Line Options. + (line 35) +* Script, from command line: Command-Line Options. + (line 30) +* sed commands syntax: sed script overview. (line 13) +* sed commands, multiple: sed script overview. (line 37) +* sed script structure: sed script overview. (line 6) +* Selecting lines to process: Numeric Addresses. (line 6) +* Selecting non-matching lines: Addresses overview. (line 31) +* semicolons, command separator: sed script overview. (line 37) +* Several lines, selecting: Range Addresses. (line 6) +* Slash character, in regular expressions: Regexp Addresses. (line 32) +* space characters: Character Classes and Bracket Expressions. + (line 80) * Spaces, pattern and hold: Execution Cycle. (line 6) -* Special addressing forms: Addresses. (line 80) -* Standard input, processing as input: Invoking sed. (line 150) +* Special addressing forms: Range Addresses. (line 31) +* standard input: Overview. (line 15) +* Standard input, processing as input: Command-Line Options. + (line 150) +* standard output: Overview. (line 23) +* stdin: Overview. (line 15) +* stdout: Overview. (line 23) * Stream editor: Introduction. (line 6) +* subexpression: Back-references and Subexpressions. + (line 6) +* Subprocesses: The "s" Command. (line 108) * Subprocesses <1>: Extended Commands. (line 12) -* Subprocesses: The "s" Command. (line 103) -* Substitution of text, options: The "s" Command. (line 65) -* Text, appending: Other Commands. (line 27) -* Text, deleting: Common Commands. (line 36) -* Text, insertion: Other Commands. (line 46) -* Text, printing: Common Commands. (line 39) -* Text, printing after substitution: The "s" Command. (line 83) +* Substitution of text, options: The "s" Command. (line 70) +* suppressing output: Overview. (line 30) +* syntax, addresses: sed script overview. (line 13) +* syntax, sed commands: sed script overview. (line 13) +* Text, appending: Other Commands. (line 45) +* Text, deleting: Common Commands. (line 44) +* Text, insertion: Other Commands. (line 104) +* Text, printing: Common Commands. (line 52) +* Text, printing after substitution: The "s" Command. (line 88) * Text, writing to a file after substitution: The "s" Command. - (line 96) -* Transliteration: Other Commands. (line 14) -* Unbuffered I/O, choosing: Invoking sed. (line 131) -* Usage summary, printing: Invoking sed. (line 28) -* Version, printing: Invoking sed. (line 24) -* Working on separate files: Invoking sed. (line 121) -* Write first line to a file: Extended Commands. (line 88) -* Write to a file: Other Commands. (line 88) -* Zero, as range start address: Addresses. (line 80) + (line 101) +* Transliteration: Other Commands. (line 11) +* Unbuffered I/O, choosing: Command-Line Options. + (line 131) +* upper-case letters: Character Classes and Bracket Expressions. + (line 84) +* Usage summary, printing: Command-Line Options. + (line 17) +* Version, printing: Command-Line Options. + (line 13) +* whitespace characters: Character Classes and Bracket Expressions. + (line 80) +* Working on separate files: Command-Line Options. + (line 115) +* Write first line to a file: Extended Commands. (line 80) +* Write to a file: Other Commands. (line 240) +* xdigit class: Character Classes and Bracket Expressions. + (line 88) +* Zero, as range start address: Range Addresses. (line 31) -File: sed.info, Node: Command and Option Index, Prev: Concept Index, Up: Top +File: sed.info-t, Node: Command and Option Index, Prev: Concept Index, Up: Top Command and Option Index ************************ -This is an alphabetical list of all `sed' commands and command-line +This is an alphabetical list of all 'sed' commands and command-line options. * Menu: * # (comments): Common Commands. (line 12) -* --binary: Invoking sed. (line 93) -* --expression: Invoking sed. (line 41) -* --file: Invoking sed. (line 46) -* --follow-symlinks: Invoking sed. (line 104) -* --help: Invoking sed. (line 28) -* --in-place: Invoking sed. (line 51) -* --line-length: Invoking sed. (line 76) -* --null-data: Invoking sed. (line 139) -* --posix: Invoking sed. (line 81) -* --quiet: Invoking sed. (line 34) -* --regexp-extended: Invoking sed. (line 113) -* --separate: Invoking sed. (line 121) -* --silent: Invoking sed. (line 34) -* --unbuffered: Invoking sed. (line 131) -* --version: Invoking sed. (line 24) -* --zero-terminated: Invoking sed. (line 139) -* -b: Invoking sed. (line 93) -* -e: Invoking sed. (line 41) -* -f: Invoking sed. (line 46) -* -i: Invoking sed. (line 51) -* -l: Invoking sed. (line 76) -* -n: Invoking sed. (line 34) +* --binary: Command-Line Options. + (line 81) +* --expression: Command-Line Options. + (line 30) +* --file: Command-Line Options. + (line 35) +* --follow-symlinks: Command-Line Options. + (line 92) +* --help: Command-Line Options. + (line 17) +* --in-place: Command-Line Options. + (line 40) +* --line-length: Command-Line Options. + (line 64) +* --null-data: Command-Line Options. + (line 139) +* --posix: Command-Line Options. + (line 69) +* --quiet: Command-Line Options. + (line 23) +* --regexp-extended: Command-Line Options. + (line 102) +* --sandbox: Command-Line Options. + (line 124) +* --separate: Command-Line Options. + (line 115) +* --silent: Command-Line Options. + (line 23) +* --unbuffered: Command-Line Options. + (line 131) +* --version: Command-Line Options. + (line 13) +* --zero-terminated: Command-Line Options. + (line 139) +* -b: Command-Line Options. + (line 81) +* -e: Command-Line Options. + (line 30) +* -E: Command-Line Options. + (line 102) +* -f: Command-Line Options. + (line 35) +* -i: Command-Line Options. + (line 40) +* -l: Command-Line Options. + (line 64) +* -n: Command-Line Options. + (line 23) * -n, forcing from within a script: Common Commands. (line 20) -* -r: Invoking sed. (line 113) -* -s: Invoking sed. (line 121) -* -u: Invoking sed. (line 131) -* -z: Invoking sed. (line 139) +* -r: Command-Line Options. + (line 102) +* -s: Command-Line Options. + (line 115) +* -u: Command-Line Options. + (line 131) +* -z: Command-Line Options. + (line 139) * : (label) command: Programming Commands. (line 14) -* = (print line number) command: Other Commands. (line 62) -* a (append text lines) command: Other Commands. (line 27) +* = (print line number) command: Other Commands. (line 194) +* {} command grouping: Common Commands. (line 91) +* a (append text lines) command: Other Commands. (line 45) +* alnum character class: Character Classes and Bracket Expressions. + (line 44) +* alpha character class: Character Classes and Bracket Expressions. + (line 49) * b (branch) command: Programming Commands. (line 18) -* c (change to text lines) command: Other Commands. (line 52) -* D (delete first line) command: Other Commands. (line 99) -* d (delete) command: Common Commands. (line 36) +* blank character class: Character Classes and Bracket Expressions. + (line 54) +* c (change to text lines) command: Other Commands. (line 157) +* cntrl character class: Character Classes and Bracket Expressions. + (line 57) +* D (delete first line) command: Other Commands. (line 251) +* d (delete) command: Common Commands. (line 44) +* digit character class: Character Classes and Bracket Expressions. + (line 62) * e (evaluate) command: Extended Commands. (line 12) * F (File name) command: Extended Commands. (line 30) -* G (appending Get) command: Other Commands. (line 125) -* g (get) command: Other Commands. (line 121) -* H (append Hold) command: Other Commands. (line 117) -* h (hold) command: Other Commands. (line 113) -* i (insert text lines) command: Other Commands. (line 46) -* L (fLow paragraphs) command: Extended Commands. (line 34) -* l (list unambiguously) command: Other Commands. (line 65) -* N (append Next line) command: Other Commands. (line 105) -* n (next-line) command: Common Commands. (line 44) -* P (print first line) command: Other Commands. (line 110) -* p (print) command: Common Commands. (line 39) -* q (quit) command: Common Commands. (line 30) -* Q (silent Quit) command: Extended Commands. (line 44) -* r (read file) command: Other Commands. (line 78) -* R (read line) command: Extended Commands. (line 61) -* s command, option flags: The "s" Command. (line 65) -* T (test and branch if failed) command: Extended Commands. (line 71) +* G (appending Get) command: Other Commands. (line 284) +* g (get) command: Other Commands. (line 280) +* graph character class: Character Classes and Bracket Expressions. + (line 65) +* H (append Hold) command: Other Commands. (line 276) +* h (hold) command: Other Commands. (line 272) +* i (insert text lines) command: Other Commands. (line 104) +* l (list unambiguously) command: Other Commands. (line 207) +* lower character class: Character Classes and Bracket Expressions. + (line 68) +* N (append Next line) command: Other Commands. (line 257) +* n (next-line) command: Common Commands. (line 61) +* P (print first line) command: Other Commands. (line 269) +* p (print) command: Common Commands. (line 52) +* print character class: Character Classes and Bracket Expressions. + (line 72) +* punct character class: Character Classes and Bracket Expressions. + (line 75) +* q (quit) command: Common Commands. (line 28) +* Q (silent Quit) command: Extended Commands. (line 36) +* r (read file) command: Other Commands. (line 219) +* R (read line) command: Extended Commands. (line 53) +* s command, option flags: The "s" Command. (line 70) +* space character class: Character Classes and Bracket Expressions. + (line 80) +* T (test and branch if failed) command: Extended Commands. (line 63) * t (test and branch if successful) command: Programming Commands. (line 22) -* v (version) command: Extended Commands. (line 77) -* w (write file) command: Other Commands. (line 88) -* W (write first line) command: Extended Commands. (line 88) -* x (eXchange) command: Other Commands. (line 129) -* y (transliterate) command: Other Commands. (line 14) -* z (Zap) command: Extended Commands. (line 93) -* {} command grouping: Common Commands. (line 50) +* upper character class: Character Classes and Bracket Expressions. + (line 84) +* v (version) command: Extended Commands. (line 69) +* w (write file) command: Other Commands. (line 240) +* W (write first line) command: Extended Commands. (line 80) +* x (eXchange) command: Other Commands. (line 288) +* xdigit character class: Character Classes and Bracket Expressions. + (line 88) +* y (transliterate) command: Other Commands. (line 11) +* z (Zap) command: Extended Commands. (line 85) Tag Table: -Node: Top944 -Node: Introduction3867 -Node: Invoking sed4421 -Ref: Invoking sed-Footnote-110793 -Ref: Invoking sed-Footnote-210985 -Node: sed Programs11084 -Node: Execution Cycle12617 -Ref: Execution Cycle-Footnote-113794 -Node: Addresses14095 -Node: Regular Expressions18996 -Node: Common Commands26905 -Node: The "s" Command28908 -Ref: The "s" Command-Footnote-134229 -Node: Other Commands34301 -Ref: Other Commands-Footnote-139501 -Node: Programming Commands39573 -Node: Extended Commands40487 -Node: Escapes44752 -Ref: Escapes-Footnote-147763 -Node: Examples47954 -Node: Centering lines49050 -Node: Increment a number49942 -Ref: Increment a number-Footnote-151419 -Node: Rename files to lower case51539 -Node: Print bash environment54312 -Node: Reverse chars of lines55067 -Ref: Reverse chars of lines-Footnote-156068 -Node: tac56285 -Node: cat -n57052 -Node: cat -b58874 -Node: wc -c59621 -Ref: wc -c-Footnote-161529 -Node: wc -w61598 -Node: wc -l63062 -Node: head63306 -Node: tail63637 -Node: uniq65318 -Node: uniq -d66106 -Node: uniq -u66817 -Node: cat -s67528 -Node: Limitations69379 -Node: Other Resources70220 -Node: Reporting Bugs71065 -Ref: Reporting Bugs-Footnote-178131 -Node: Extended regexps78202 -Node: Concept Index79517 -Node: Command and Option Index94612 +Node: Top728 +Node: Introduction2176 +Node: Invoking sed2732 +Node: Overview3047 +Node: Command-Line Options5306 +Ref: Command-Line Options-Footnote-111851 +Ref: Command-Line Options-Footnote-212043 +Node: Exit status12142 +Node: sed scripts13046 +Node: sed script overview13561 +Node: sed commands list16049 +Node: The "s" Command20854 +Ref: The "s" Command-Footnote-126320 +Node: Common Commands26392 +Node: Other Commands29424 +Ref: Other Commands-Footnote-138450 +Node: Programming Commands38522 +Node: Extended Commands39436 +Node: sed addresses43302 +Node: Addresses overview43733 +Node: Numeric Addresses45511 +Node: Regexp Addresses46864 +Ref: Regexp Addresses-Footnote-150251 +Node: Range Addresses50391 +Node: sed regular expressions52873 +Node: Regular Expressions Overview53675 +Node: BRE vs ERE55184 +Node: BRE syntax56778 +Node: ERE syntax63165 +Node: Character Classes and Bracket Expressions64639 +Node: regexp extensions69479 +Node: Back-references and Subexpressions71869 +Node: Escapes74275 +Ref: Escapes-Footnote-176473 +Node: Locale Considerations76664 +Node: advanced sed77935 +Node: Execution Cycle78296 +Ref: Execution Cycle-Footnote-179493 +Node: Hold and Pattern Buffers79794 +Node: Multiline techniques79984 +Node: Branching and flow control83200 +Node: Examples83372 +Node: Joining lines84574 +Node: Centering lines85229 +Node: Increment a number86148 +Ref: Increment a number-Footnote-187627 +Node: Rename files to lower case87747 +Node: Print bash environment90522 +Node: Reverse chars of lines91279 +Ref: Reverse chars of lines-Footnote-192312 +Node: Text search across multiple lines92529 +Node: Line length adjustment95756 +Node: tac98182 +Node: cat -n98951 +Node: cat -b100775 +Node: wc -c101526 +Ref: wc -c-Footnote-1103438 +Node: wc -w103507 +Node: wc -l104973 +Node: head105220 +Node: tail105553 +Node: uniq107236 +Node: uniq -d108025 +Node: uniq -u108738 +Node: cat -s109449 +Node: Limitations111298 +Node: Other Resources112141 +Node: Reporting Bugs112988 +Ref: N_command_last_line114153 +Ref: Reporting Bugs-Footnote-1120298 +Node: GNU Free Documentation License120369 +Node: Concept Index145524 +Node: Command and Option Index170108 End Tag Table |