ln -f

ln.1

@@ -3,12 +3,12 @@
 ln \- make links between files
 .SH SYNOPSIS
 .B ln
-.RB [ \-s ]
+.RB [ \-fs ]
 .I file
 .RI [ name ]
 .P
 .B ln
-.RB [ \-s ]
+.RB [ \-fs ]
 .RI [ file ...]
 .RI [ directory ]
 .SH DESCRIPTION
@@ -18,6 +18,9 @@ it is linked into the current directory.  If multiple files are listed they will
 be linked into the given directory.
 .SH OPTIONS
 .TP
+.B \-f
+remove existing destinations.
+.TP
 .B \-s
 create a symlink.
 .SH SEE ALSO

ln.c

@@ -1,23 +1,40 @@
 /* See LICENSE file for copyright and license details. */
+#include <errno.h>
 #include <stdbool.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include "util.h"
 
+static int ln(const char *, const char *);
+
+static bool sflag = false;
+static bool fflag = false;
+
 int
 main(int argc, char *argv[])
 {
-	bool sflag = false;
 	char c;
 
-	while((c = getopt(argc, argv, "s")) != -1)
+	while((c = getopt(argc, argv, "fs")) != -1)
 		switch(c) {
+		case 'f':
+			fflag = true;
+			break;
 		case 's':
 			sflag = true;
 			break;
 		default:
 			exit(EXIT_FAILURE);
 		}
-	enmasse(argc - optind, &argv[optind], sflag ? symlink : link);
+	enmasse(argc - optind, &argv[optind], ln);
 	return EXIT_SUCCESS;
 }
+
+int
+ln(const char *s1, const char *s2)
+{
+	if(fflag && remove(s2) != 0 && errno != ENOENT)
+		eprintf("remove %s:", s2);
+	return (sflag ? symlink : link)(s1, s2);
+}

uname.c

@@ -40,7 +40,7 @@ main(int argc, char *argv[])
 		default:
 			exit(EXIT_FAILURE);
 		}
-	if(uname(&u) == -1)
+	if(uname(&u) != 0)
 		eprintf("uname:");
 
 	if(sflag || !(nflag || rflag || vflag || mflag))