1 files changed, 36 insertions, 0 deletions
diff --git a/src/utilfuns/sub.c b/src/utilfuns/sub.c
new file mode 100644
index 0000000..fcea6e2
--- /dev/null
+++ b/src/utilfuns/sub.c
@@ -0,0 +1,36 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+
+main(int argc, char **argv)
+{
+	FILE *fp;
+	char *buf;
+	int size;
+
+	if ((argc < 3) || (argc > 4)) {
+		fprintf(stderr, "usage: %s <string> <substitute string> [filename]\n", *argv);
+		exit(-1);
+	}
+
+	if (argc > 3)
+		fp = fopen(argv[3], "r");
+	else	fp = stdin;
+
+	size = strlen(argv[1]);
+	buf = (char *)calloc(size + 1, 1);
+
+	while ((buf[size - 1] = fgetc(fp)) != EOF) {
+		if (!strcmp(buf, argv[1])) {
+			printf("\n%s", argv[2]);
+			memset(buf, 0, size);
+			continue;
+		}
+		if (*buf) {
+			printf("%c", *buf);
+		}
+		memmove(buf, &buf[1], size);
+	}
+	buf[size - 1] = 0;
+	printf("%s", buf);
+}