Add logname(1)

logname.c

@@ -0,0 +1,20 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <unistd.h>
+
+#include "util.h"
+
+int
+main(int argc, char *argv[])
+{
+	char *login;
+
+	argv0 = argv[0];
+	if (argc != 1)
+		eprintf("usage: %s\n", argv0);
+	if ((login = getlogin()))
+		printf("%s\n", login);
+	else
+		eprintf("%s: no login name\n", argv0);
+	return 0;
+}