add dirname

Makefile

@@ -1,7 +1,8 @@
 include config.mk
 
 LIB = util/enmasse.o util/eprintf.o
-SRC = basename.c cat.c date.c echo.c false.c grep.c ln.c pwd.c rm.c sleep.c tee.c touch.c true.c wc.c
+SRC = basename.c cat.c date.c dirname.c echo.c false.c grep.c ln.c pwd.c rm.c \
+      sleep.c tee.c touch.c true.c wc.c
 OBJ = $(SRC:.c=.o) $(LIB)
 BIN = $(SRC:.c=)
 MAN = $(SRC:.c=.1)

basename.1

@@ -1,6 +1,6 @@
 .TH BASENAME 1 sbase\-VERSION
 .SH NAME
-basename \- strip directory from filename
+basename \- strip leading path component
 .SH SYNOPSIS
 .B basename
 .I string
@@ -9,6 +9,6 @@ basename \- strip directory from filename
 .B basename
 prints the
 .I string
-with any leading directory components, and the
+with any leading path components, and the
 .IR suffix ,
 removed.

basename.c

@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 #include "util.h"
 
 int
@@ -11,13 +12,15 @@ main(int argc, char *argv[])
 	char *s;
 	size_t n;
 
-	if(argc < 2)
+	if(getopt(argc, argv, "") != -1)
+		exit(EXIT_FAILURE);
+	if(optind == argc)
 		eprintf("usage: %s string [suffix]\n", argv[0]);
 
-	s = basename(argv[1]);
+	s = basename(argv[optind++]);
-	if(argc > 2 && strlen(s) > strlen(argv[2])) {
+	if(optind < argc && strlen(s) > strlen(argv[optind])) {
-		n = strlen(s) - strlen(argv[2]);
+		n = strlen(s) - strlen(argv[optind]);
-		if(!strcmp(&s[n], argv[2]))
+		if(!strcmp(&s[n], argv[optind]))
 			s[n] = '\0';
 	}
 	puts(s);

dirname.1

@@ -0,0 +1,11 @@
+.TH DIRNAME 1 sbase\-VERSION
+.SH NAME
+dirname \- strip final path component
+.SH SYNOPSIS
+.B dirname
+.I string
+.SH DESCRIPTION
+.B dirname
+prints the
+.I string
+with its final path component removed.

dirname.c

@@ -0,0 +1,18 @@
+/* See LICENSE file for copyright and license details. */
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "util.h"
+
+int
+main(int argc, char *argv[])
+{
+	if(getopt(argc, argv, "") != -1)
+		exit(EXIT_FAILURE);
+	if(optind != argc-1)
+		eprintf("usage: %s string\n", argv[0]);
+
+	puts(dirname(argv[optind]));
+	return EXIT_SUCCESS;
+}