Adding the new C files too.

chgrp.c

@@ -0,0 +1,72 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <ftw.h>
+#include <errno.h>
+#include <grp.h>
+#include <sys/types.h>
+#include "util.h"
+
+int gid;
+int failures = 0;
+
+static void
+usage(void)
+{
+	eprintf("usage: chgrp [-R] groupname file...\n");
+}
+
+static int
+chgrp(const char *path, const struct stat *st, int f)
+{
+	(void)f;
+
+	if(chown(path, st->st_uid, gid) == -1) {
+		fprintf(stderr, "chgrp: '%s': %s\n", path, strerror(errno));
+		failures++;
+	}
+
+	return 0;
+}
+
+int
+main(int argc, char **argv)
+{
+	int rflag = 0;
+	struct group *gr;
+	struct stat st;
+
+	ARGBEGIN {
+	case 'R':
+		rflag = 1;
+		break;
+	default:
+		usage();
+	} ARGEND;
+	if(argc<2)
+		usage();
+
+	gr = getgrnam(argv[0]);
+	if(!gr)
+		eprintf("chgrp: '%s': No such group\n", argv[0]);
+	gid = gr->gr_gid;
+
+	if(rflag) {
+		while(*++argv)
+			ftw(*argv, chgrp, FOPEN_MAX);
+
+		return 0;
+	}
+	while(*++argv) {
+		if(stat(*argv, &st) == -1) {
+			fprintf(stderr, "chgrp: '%s': %s\n", *argv,
+					strerror(errno));
+			failures++;
+			continue;
+		}
+		chgrp(*argv, &st, 0);
+	}
+
+	return failures;
+}
+

chvt.c

@@ -0,0 +1,61 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include "util.h"
+
+enum {
+	/* from <linux/vt.h> */
+	VT_ACTIVATE = 0x5606,
+	VT_WAITACTIVE = 0x5607,
+	/* from <linux/kd.h> */
+	KDGKBTYPE = 0x4B33
+};
+
+char *vts[] = {
+	"/proc/self/fd/0",
+	"/dev/console",
+	"/dev/tty",
+	"/dev/tty0",
+};
+
+static void
+usage(void)
+{
+	eprintf("usage: chvt N\n");
+}
+
+int
+main(int argc, char **argv)
+{
+	int n, i, fd;
+	char c;
+
+	if(argc!=2 || strspn(argv[1], "1234567890") != strlen(argv[1]))
+		usage();
+
+	n = atoi(argv[1]);
+	for(i = 0; i < LEN(vts); i++) {
+		fd = open(vts[i], O_RDONLY);
+		if(fd < 1)
+			continue;
+		c = 0;
+		if(ioctl(fd, KDGKBTYPE, &c) == 0)
+			goto VTfound;
+		close(fd);
+	}
+
+	eprintf("chvt: couldn't find a console.\n");
+VTfound:
+	if(ioctl(fd, VT_ACTIVATE, n) == -1)
+		eprintf("chvt: VT_ACTIVATE '%d':", n);
+	if(ioctl(fd, VT_WAITACTIVE, n) == -1)
+		eprintf("chvt: VT_WAITACTIVE '%d':", n);
+	close(fd);
+
+	return 0;
+}
+

nice.c

@@ -0,0 +1,38 @@
+/* See LICENSE file for copyright and license details. */
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: nice [-n inc] command [options ...]\n");
+}
+
+int
+main(int argc, char **argv)
+{
+	int inc = 10;
+
+	ARGBEGIN {
+	case 'n':
+		inc = atoi(EARGF(usage()));
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	nice(inc); /* POSIX specifies the nice failure still invokes the command. */
+
+	if(!*argv)
+		usage();
+
+	execvp(*argv, argv);
+	eprintf("nice: '%s': %s\n", *argv, strerror(errno));
+
+	return EXIT_FAILURE;
+}
+

printenv.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+extern char **environ;
+
+int
+main(int argc, char **argv)
+{
+	char *var;
+
+	if(argc == 1) {
+		while(*environ)
+			printf("%s\n", *environ++);
+
+		return 0;
+	}
+	while(*++argv) {
+		if((var = getenv(*argv)))
+			printf("%s\n", var);
+	}
+
+	return 0;
+}
+

rmdir.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: rmdir dir...\n");
+}
+
+int
+main(int argc, char **argv)
+{
+	argv++;;
+	if(!*argv)
+		usage();
+
+	while(*argv) {
+		if(rmdir(*argv++) == -1)
+			fprintf(stderr, "rmdir: '%s': %s\n",
+					argv[-1], strerror(errno));
+	}
+
+	return 0;
+}
+

sync.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <unistd.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: sync\n");
+}
+
+int
+main(int argc, char **argv)
+{
+	if(argc != 1)
+		usage();
+	sync();
+
+	return 0;
+}
+

unlink.c

@@ -0,0 +1,21 @@
+#include <unistd.h>
+#include "util.h"
+
+static void
+usage(void)
+{
+	eprintf("usage: unlink file\n");
+}
+
+int
+main(int argc, char **argv)
+{
+	if(argc != 2)
+		usage();
+
+	if(unlink(argv[1]) == -1)
+		eprintf("unlink: '%s':", argv[1]);
+
+	return 0;
+}
+