Add strings(1)

Makefile

@@ -70,6 +70,7 @@ SRC = \
 	sort.c     \
 	split.c    \
 	sponge.c   \
+	strings.c  \
 	sync.c     \
 	tail.c     \
 	tar.c      \

strings.1

@@ -0,0 +1,10 @@
+.TH STRINGS 1 sbase\-VERSION
+.SH NAME
+strings \- print the strings of printable characters in files
+.SH SYNOPSIS
+.B strings
+.IR [file...]
+.SH DESCRIPTION
+.B strings
+prints the printable character sequences that are at least 6 characters
+long.  If no files are given then it uses stdin.

strings.c

@@ -0,0 +1,56 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include "util.h"
+
+static void dostrings(FILE *fp, const char *fname);
+
+static void
+usage(void)
+{
+	eprintf("usage: %s file\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	FILE *fp;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc > 0) {
+		if (!(fp = fopen(argv[0], "r")))
+			eprintf("open %s:", argv[0]);
+		dostrings(fp, argv[0]);
+		fclose(fp);
+	} else {
+		dostrings(stdin, "<stdin>");
+	}
+
+	return 0;
+}
+
+static void
+dostrings(FILE *fp, const char *fname)
+{
+	unsigned char buf[BUFSIZ];
+	int c, i = 0;
+	off_t offset = 0;
+
+	do {
+		offset++;
+		if (isprint(c = getc(fp)))
+			buf[i++] = c;
+		if ((!isprint(c) && i >= 6) || i == sizeof(buf) - 1) {
+			buf[i] = '\0';
+			printf("%8ld: %s\n", (long)offset - i - 1, buf);
+			i = 0;
+		}
+	} while (c != EOF);
+	if (ferror(fp))
+		eprintf("%s: read error:", fname);
+}