diff --git a/usr.bin/ar/util.c b/usr.bin/ar/util.c
index e1230e33013..621c2b8a197 100644
--- a/usr.bin/ar/util.c
+++ b/usr.bin/ar/util.c
@@ -29,7 +29,6 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/queue.h>
 #include <sys/types.h>
-#include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/c89/c89.c b/usr.bin/c89/c89.c
index a1dc9b2a623..f8c47c5d11f 100644
--- a/usr.bin/c89/c89.c
+++ b/usr.bin/c89/c89.c
@@ -33,7 +33,6 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 
 #include <unistd.h>
 
diff --git a/usr.bin/calendar/calendar.c b/usr.bin/calendar/calendar.c
index d1bb74516d9..39f2c9ce23f 100644
--- a/usr.bin/calendar/calendar.c
+++ b/usr.bin/calendar/calendar.c
@@ -55,7 +55,6 @@ __FBSDID("$FreeBSD$");
 #include <time.h>
 #include <unistd.h>
 
-#include "pathnames.h"
 #include "calendar.h"
 
 struct passwd	*pw;
diff --git a/usr.bin/calendar/day.c b/usr.bin/calendar/day.c
index d3f3c1ec4f2..e40481eb918 100644
--- a/usr.bin/calendar/day.c
+++ b/usr.bin/calendar/day.c
@@ -44,7 +44,6 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 #include <time.h>
 
-#include "pathnames.h"
 #include "calendar.h"
 
 struct tm		*tp;
diff --git a/usr.bin/calendar/ostern.c b/usr.bin/calendar/ostern.c
index 76e593327a3..93e9c07b44f 100644
--- a/usr.bin/calendar/ostern.c
+++ b/usr.bin/calendar/ostern.c
@@ -30,7 +30,6 @@ __FBSDID("$FreeBSD$");
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 
 #include "calendar.h"
 
diff --git a/usr.bin/calendar/paskha.c b/usr.bin/calendar/paskha.c
index d96ffc2546e..e713f5f9be9 100644
--- a/usr.bin/calendar/paskha.c
+++ b/usr.bin/calendar/paskha.c
@@ -30,7 +30,6 @@ __FBSDID("$FreeBSD$");
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 
 #include "calendar.h"
 
diff --git a/usr.bin/cksum/Makefile b/usr.bin/cksum/Makefile
index 828900ac027..7ba38032fdb 100644
--- a/usr.bin/cksum/Makefile
+++ b/usr.bin/cksum/Makefile
@@ -5,5 +5,6 @@ PROG=	cksum
 SRCS=	cksum.c crc.c print.c sum1.c sum2.c crc32.c
 LINKS=	${BINDIR}/cksum ${BINDIR}/sum
 MLINKS=	cksum.1 sum.1
+WARNS?=	6
 
 .include <bsd.prog.mk>
diff --git a/usr.bin/cksum/crc.c b/usr.bin/cksum/crc.c
index d1f42f2f628..ee48278c38f 100644
--- a/usr.bin/cksum/crc.c
+++ b/usr.bin/cksum/crc.c
@@ -44,7 +44,6 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 
-#include <stdint.h>
 #include <unistd.h>
 
 #include "extern.h"
diff --git a/usr.bin/cksum/crc32.c b/usr.bin/cksum/crc32.c
index cadbc17b69b..eefa7724eb9 100644
--- a/usr.bin/cksum/crc32.c
+++ b/usr.bin/cksum/crc32.c
@@ -17,7 +17,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 
 #include <stdio.h>
-#include <stdint.h>
 #include <unistd.h>
 
 #include "extern.h"
diff --git a/usr.bin/cksum/sum1.c b/usr.bin/cksum/sum1.c
index 406b40e2832..e6dd910bfee 100644
--- a/usr.bin/cksum/sum1.c
+++ b/usr.bin/cksum/sum1.c
@@ -43,7 +43,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 
 #include <unistd.h>
-#include <stdint.h>
 
 #include "extern.h"
 
diff --git a/usr.bin/cksum/sum2.c b/usr.bin/cksum/sum2.c
index c179c6289a2..b4380623a64 100644
--- a/usr.bin/cksum/sum2.c
+++ b/usr.bin/cksum/sum2.c
@@ -42,7 +42,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 
 #include <unistd.h>
-#include <stdint.h>
 
 #include "extern.h"
 
diff --git a/usr.bin/cmp/regular.c b/usr.bin/cmp/regular.c
index 814d9333b93..555725a999b 100644
--- a/usr.bin/cmp/regular.c
+++ b/usr.bin/cmp/regular.c
@@ -45,12 +45,10 @@ __FBSDID("$FreeBSD$");
 #include <sys/stat.h>
 
 #include <err.h>
-#include <errno.h>
 #include <limits.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <stdio.h>
-#include <string.h>
 #include <unistd.h>
 
 #include "extern.h"
diff --git a/usr.bin/cmp/special.c b/usr.bin/cmp/special.c
index bbe3cb10fa8..e5e8325d109 100644
--- a/usr.bin/cmp/special.c
+++ b/usr.bin/cmp/special.c
@@ -45,7 +45,6 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <stdlib.h>
 #include <stdio.h>
-#include <string.h>
 
 #include "extern.h"
 
diff --git a/usr.bin/colcrt/colcrt.c b/usr.bin/colcrt/colcrt.c
index 2ba4f39bbda..f8452514d8c 100644
--- a/usr.bin/colcrt/colcrt.c
+++ b/usr.bin/colcrt/colcrt.c
@@ -50,7 +50,6 @@ __FBSDID("$FreeBSD$");
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 #include <wchar.h>
 
diff --git a/usr.bin/colrm/colrm.c b/usr.bin/colrm/colrm.c
index 52dda90086d..399252aaa34 100644
--- a/usr.bin/colrm/colrm.c
+++ b/usr.bin/colrm/colrm.c
@@ -48,12 +48,9 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <err.h>
-#include <errno.h>
-#include <limits.h>
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 #include <wchar.h>
 
diff --git a/usr.bin/compress/zopen.c b/usr.bin/compress/zopen.c
index f0ec8871cd8..92e0a971fea 100644
--- a/usr.bin/compress/zopen.c
+++ b/usr.bin/compress/zopen.c
@@ -67,13 +67,11 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/stat.h>
 
-#include <ctype.h>
 #include <errno.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 #include "zopen.h"
 
 #define	BITS		16		/* Default bits. */
diff --git a/usr.bin/cpuset/cpuset.c b/usr.bin/cpuset/cpuset.c
index 35b13afa0a4..a2bcf889d4d 100644
--- a/usr.bin/cpuset/cpuset.c
+++ b/usr.bin/cpuset/cpuset.c
@@ -44,7 +44,6 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 #include <stdint.h>
 #include <unistd.h>
-#include <string.h>
 
 int cflag;
 int gflag;
diff --git a/usr.bin/expand/expand.c b/usr.bin/expand/expand.c
index 6c99db80685..9f04799d911 100644
--- a/usr.bin/expand/expand.c
+++ b/usr.bin/expand/expand.c
@@ -52,7 +52,6 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 #include <unistd.h>
 #include <wchar.h>
-#include <wctype.h>
 
 /*
  * expand - expand tabs to equivalent spaces
diff --git a/usr.bin/fetch/fetch.c b/usr.bin/fetch/fetch.c
index 2512a2e8632..8fe419b7b05 100644
--- a/usr.bin/fetch/fetch.c
+++ b/usr.bin/fetch/fetch.c
@@ -34,7 +34,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/stat.h>
 #include <sys/time.h>
 
-#include <ctype.h>
 #include <err.h>
 #include <errno.h>
 #include <signal.h>
diff --git a/usr.bin/file2c/file2c.c b/usr.bin/file2c/file2c.c
index e50bd1f8a46..8affbd07f78 100644
--- a/usr.bin/file2c/file2c.c
+++ b/usr.bin/file2c/file2c.c
@@ -10,7 +10,6 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
diff --git a/usr.bin/find/find.c b/usr.bin/find/find.c
index cc2d797a541..3171f8ba595 100644
--- a/usr.bin/find/find.c
+++ b/usr.bin/find/find.c
@@ -52,7 +52,6 @@ __FBSDID("$FreeBSD$");
 #include <fts.h>
 #include <regex.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
 #include "find.h"
diff --git a/usr.bin/find/getdate.y b/usr.bin/find/getdate.y
index de7750c88ff..0a7ab21087a 100644
--- a/usr.bin/find/getdate.y
+++ b/usr.bin/find/getdate.y
@@ -15,7 +15,6 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdio.h>
 #include <ctype.h>
 
 /* The code at the top of get_date which figures out the offset of the
diff --git a/usr.bin/find/ls.c b/usr.bin/find/ls.c
index 88e45938cc6..7b9d88f4731 100644
--- a/usr.bin/find/ls.c
+++ b/usr.bin/find/ls.c
@@ -44,7 +44,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/stat.h>
 
 #include <err.h>
-#include <errno.h>
 #include <fts.h>
 #include <grp.h>
 #include <inttypes.h>
diff --git a/usr.bin/find/main.c b/usr.bin/find/main.c
index 8e2b42cd298..9a0b9ce4c74 100644
--- a/usr.bin/find/main.c
+++ b/usr.bin/find/main.c
@@ -53,7 +53,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/stat.h>
 
 #include <err.h>
-#include <errno.h>
 #include <fcntl.h>
 #include <fts.h>
 #include <locale.h>
diff --git a/usr.bin/find/misc.c b/usr.bin/find/misc.c
index 15329064cf4..8fda57c87df 100644
--- a/usr.bin/find/misc.c
+++ b/usr.bin/find/misc.c
@@ -48,7 +48,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/stat.h>
 
 #include <err.h>
-#include <errno.h>
 #include <fts.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/find/option.c b/usr.bin/find/option.c
index 7d06c910ae7..6c76bbfa89b 100644
--- a/usr.bin/find/option.c
+++ b/usr.bin/find/option.c
@@ -49,7 +49,6 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <fts.h>
 #include <regex.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/usr.bin/finger/lprint.c b/usr.bin/finger/lprint.c
index 848bbeeeb32..d656693f0aa 100644
--- a/usr.bin/finger/lprint.c
+++ b/usr.bin/finger/lprint.c
@@ -310,7 +310,7 @@ show_text(const char *directory, const char *file_name, const char *header)
 		return(0);
 
 	/* If short enough, and no newlines, show it on a single line.*/
-	if (sb.st_size <= LINE_LEN - strlen(header) - 5) {
+	if (sb.st_size <= (int)(LINE_LEN - strlen(header) - 5)) {
 		nr = read(fd, tbuf, sizeof(tbuf));
 		if (nr <= 0) {
 			(void)close(fd);
diff --git a/usr.bin/finger/net.c b/usr.bin/finger/net.c
index 5260a2d6ca2..703ff60a86a 100644
--- a/usr.bin/finger/net.c
+++ b/usr.bin/finger/net.c
@@ -230,7 +230,7 @@ trying(const struct addrinfo *ai)
 	printf("Trying %s...\n", buf);
 }
 
-void
+static void
 cleanup(int sig __unused)
 {
 #define	ERRSTR	"Timed out.\n"
diff --git a/usr.bin/finger/util.c b/usr.bin/finger/util.c
index a84c711745c..3eabd34b37d 100644
--- a/usr.bin/finger/util.c
+++ b/usr.bin/finger/util.c
@@ -120,7 +120,7 @@ enter_lastlog(PERSON *pn)
 	}
 	if (fd == -1 ||
 	    lseek(fd, (long)pn->uid * sizeof(ll), SEEK_SET) !=
-	    (long)pn->uid * sizeof(ll) ||
+	    (off_t)(pn->uid * sizeof(ll)) ||
 	    read(fd, (char *)&ll, sizeof(ll)) != sizeof(ll)) {
 			/* as if never logged in */
 			ll.ll_line[0] = ll.ll_host[0] = '\0';
diff --git a/usr.bin/fmt/fmt.c b/usr.bin/fmt/fmt.c
index ed85c2e49f2..1ce93346865 100644
--- a/usr.bin/fmt/fmt.c
+++ b/usr.bin/fmt/fmt.c
@@ -180,7 +180,6 @@ __FBSDID("$FreeBSD$");
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <sysexits.h>
 #include <unistd.h>
 #include <wchar.h>
diff --git a/usr.bin/fold/fold.c b/usr.bin/fold/fold.c
index 59d8fc59adf..6c7fafb4553 100644
--- a/usr.bin/fold/fold.c
+++ b/usr.bin/fold/fold.c
@@ -54,7 +54,6 @@ __FBSDID("$FreeBSD$");
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 #include <wchar.h>
 #include <wctype.h>
diff --git a/usr.bin/gcore/gcore.c b/usr.bin/gcore/gcore.c
index 35d5363f143..706620c0c39 100644
--- a/usr.bin/gcore/gcore.c
+++ b/usr.bin/gcore/gcore.c
@@ -68,7 +68,6 @@ __FBSDID("$FreeBSD$");
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 
 #include "extern.h"
diff --git a/usr.bin/getopt/getopt.c b/usr.bin/getopt/getopt.c
index d1671a71e5e..d0355d83e7c 100644
--- a/usr.bin/getopt/getopt.c
+++ b/usr.bin/getopt/getopt.c
@@ -7,7 +7,6 @@ __FBSDID("$FreeBSD$");
  */
 
 #include <stdio.h>
-#include <stdlib.h>
 #include <unistd.h>
 
 int
diff --git a/usr.bin/hexdump/display.c b/usr.bin/hexdump/display.c
index db04c49aade..3d6a6ea8ba4 100644
--- a/usr.bin/hexdump/display.c
+++ b/usr.bin/hexdump/display.c
@@ -47,7 +47,6 @@ __FBSDID("$FreeBSD$");
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 #include "hexdump.h"
 
 enum _vflag vflag = FIRST;
diff --git a/usr.bin/hexdump/hexdump.c b/usr.bin/hexdump/hexdump.c
index 2ed7c4b9df4..a0355317316 100644
--- a/usr.bin/hexdump/hexdump.c
+++ b/usr.bin/hexdump/hexdump.c
@@ -48,7 +48,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 #include <locale.h>
 #include <stdlib.h>
-#include <stdio.h>
 #include <string.h>
 #include "hexdump.h"
 
diff --git a/usr.bin/jot/jot.c b/usr.bin/jot/jot.c
index 2e33d41be59..4cd7433556f 100644
--- a/usr.bin/jot/jot.c
+++ b/usr.bin/jot/jot.c
@@ -59,7 +59,6 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 #include <stdbool.h>
 #include <string.h>
-#include <time.h>
 #include <unistd.h>
 
 /* Defaults */
diff --git a/usr.bin/killall/killall.c b/usr.bin/killall/killall.c
index 0a779fdcbc3..6ac53ddcdcb 100644
--- a/usr.bin/killall/killall.c
+++ b/usr.bin/killall/killall.c
@@ -34,8 +34,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/uio.h>
 #include <sys/user.h>
 #include <sys/sysctl.h>
-#include <fcntl.h>
-#include <dirent.h>
 #include <jail.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/ktrace/subr.c b/usr.bin/ktrace/subr.c
index a9d3f6442cb..4f41a13a1b4 100644
--- a/usr.bin/ktrace/subr.c
+++ b/usr.bin/ktrace/subr.c
@@ -47,8 +47,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/uio.h>
 #include <sys/ktrace.h>
 
-#include <stdio.h>
-
 #include "ktrace.h"
 
 void timevaladd(struct timeval *, struct timeval *);
diff --git a/usr.bin/lastcomm/lastcomm.c b/usr.bin/lastcomm/lastcomm.c
index 8c551231a4f..b5ca6dddd37 100644
--- a/usr.bin/lastcomm/lastcomm.c
+++ b/usr.bin/lastcomm/lastcomm.c
@@ -51,9 +51,6 @@ __FBSDID("$FreeBSD$");
 
 #include <ctype.h>
 #include <err.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <grp.h>
 #include <pwd.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/lastcomm/pathnames.h b/usr.bin/lastcomm/pathnames.h
index 0737970dab9..04af4402064 100644
--- a/usr.bin/lastcomm/pathnames.h
+++ b/usr.bin/lastcomm/pathnames.h
@@ -31,8 +31,8 @@
  * SUCH DAMAGE.
  *
  *	@(#)pathnames.h	8.1 (Berkeley) 6/6/93
+ *
+ * $FreeBSD$
  */
 
-#include <paths.h>
-
 #define	_PATH_ACCT	"/var/account/acct"
diff --git a/usr.bin/lastcomm/readrec.c b/usr.bin/lastcomm/readrec.c
index 4883b2a4ef8..5de7c5c4c80 100644
--- a/usr.bin/lastcomm/readrec.c
+++ b/usr.bin/lastcomm/readrec.c
@@ -33,13 +33,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 #include <sys/acct.h>
 
-#include <ctype.h>
-#include <err.h>
 #include <errno.h>
-#include <fcntl.h>
 #include <stddef.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
 int	 readrec_forward(FILE *f, struct acctv2 *av2);
diff --git a/usr.bin/limits/limits.c b/usr.bin/limits/limits.c
index 2da69a23c64..9c250f9f40c 100644
--- a/usr.bin/limits/limits.c
+++ b/usr.bin/limits/limits.c
@@ -32,7 +32,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <stdarg.h>
 #include <stdint.h>
 #include <ctype.h>
 #include <errno.h>
diff --git a/usr.bin/lock/lock.c b/usr.bin/lock/lock.c
index 3b19e35bbe1..d5812847fd6 100644
--- a/usr.bin/lock/lock.c
+++ b/usr.bin/lock/lock.c
@@ -62,7 +62,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/signal.h>
 #include <sys/consio.h>
 #include <err.h>
-#include <ctype.h>
 #include <errno.h>
 #include <pwd.h>
 #include <stdio.h>
diff --git a/usr.bin/login/login.c b/usr.bin/login/login.c
index 2a429247d9a..dd63d9233b6 100644
--- a/usr.bin/login/login.c
+++ b/usr.bin/login/login.c
@@ -64,8 +64,8 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <errno.h>
 #include <grp.h>
-#include <libutil.h>
 #include <login_cap.h>
+#include <paths.h>
 #include <pwd.h>
 #include <setjmp.h>
 #include <signal.h>
diff --git a/usr.bin/login/login_fbtab.c b/usr.bin/login/login_fbtab.c
index f6111a1cd35..c3cb8f4e736 100644
--- a/usr.bin/login/login_fbtab.c
+++ b/usr.bin/login/login_fbtab.c
@@ -71,7 +71,6 @@ __FBSDID("$FreeBSD$");
 #include <syslog.h>
 #include <unistd.h>
 
-#include "login.h"
 #include "pathnames.h"
 
 static void	login_protect(const char *, char *, int, uid_t, gid_t);
diff --git a/usr.bin/login/pathnames.h b/usr.bin/login/pathnames.h
index 60fecc24114..afb06efc6ba 100644
--- a/usr.bin/login/pathnames.h
+++ b/usr.bin/login/pathnames.h
@@ -34,8 +34,6 @@
  * $FreeBSD$
  */
 
-#include <paths.h>
-
 #define	_PATH_HUSHLOGIN		".hushlogin"
 #define	_PATH_MOTDFILE		"/etc/motd"
 #define _PATH_FBTAB		"/etc/fbtab"
diff --git a/usr.bin/mesg/mesg.c b/usr.bin/mesg/mesg.c
index 270c1c546b5..7f891cc399c 100644
--- a/usr.bin/mesg/mesg.c
+++ b/usr.bin/mesg/mesg.c
@@ -56,7 +56,6 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 
 static void usage(void);
diff --git a/usr.bin/mkfifo/mkfifo.c b/usr.bin/mkfifo/mkfifo.c
index 7e147b6b149..468656203e4 100644
--- a/usr.bin/mkfifo/mkfifo.c
+++ b/usr.bin/mkfifo/mkfifo.c
@@ -52,7 +52,6 @@ __FBSDID("$FreeBSD$");
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 
 #define	BASEMODE	S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | \
diff --git a/usr.bin/mklocale/yacc.y b/usr.bin/mklocale/yacc.y
index 344af220cf6..99d86e6b7fc 100644
--- a/usr.bin/mklocale/yacc.y
+++ b/usr.bin/mklocale/yacc.y
@@ -48,7 +48,6 @@ __FBSDID("$FreeBSD$");
 
 #include <ctype.h>
 #include <err.h>
-#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/usr.bin/mktemp/mktemp.c b/usr.bin/mktemp/mktemp.c
index b58ac4b9d05..72b89d60788 100644
--- a/usr.bin/mktemp/mktemp.c
+++ b/usr.bin/mktemp/mktemp.c
@@ -143,7 +143,7 @@ main(int argc, char **argv)
 }
 
 static void
-usage()
+usage(void)
 {
 	fprintf(stderr,
 		"usage: mktemp [-d] [-q] [-t prefix] [-u] template ...\n");
diff --git a/usr.bin/ncal/ncal.c b/usr.bin/ncal/ncal.c
index a65a2fcf8a2..4699025301b 100644
--- a/usr.bin/ncal/ncal.c
+++ b/usr.bin/ncal/ncal.c
@@ -30,7 +30,6 @@ static const char rcsid[] =
 #endif /* not lint */
 
 #include <calendar.h>
-#include <ctype.h>
 #include <err.h>
 #include <langinfo.h>
 #include <locale.h>
diff --git a/usr.bin/netstat/atalk.c b/usr.bin/netstat/atalk.c
index 9ed48209076..cf82020bb27 100644
--- a/usr.bin/netstat/atalk.c
+++ b/usr.bin/netstat/atalk.c
@@ -52,8 +52,6 @@ __FBSDID("$FreeBSD$");
 #include <netatalk/at.h>
 #include <netatalk/ddp_var.h>
 
-#include <errno.h>
-#include <nlist.h>
 #include <netdb.h>
 #include <stdint.h>
 #include <stdio.h>
diff --git a/usr.bin/netstat/bpf.c b/usr.bin/netstat/bpf.c
index 2ffeacbc7de..2f862e19ebf 100644
--- a/usr.bin/netstat/bpf.c
+++ b/usr.bin/netstat/bpf.c
@@ -47,7 +47,6 @@ __FBSDID("$FreeBSD$");
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 
 #include "netstat.h"
 
diff --git a/usr.bin/netstat/if.c b/usr.bin/netstat/if.c
index 02f390a0196..043a20ff0ea 100644
--- a/usr.bin/netstat/if.c
+++ b/usr.bin/netstat/if.c
@@ -68,7 +68,6 @@ __FBSDID("$FreeBSD$");
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 
 #include "netstat.h"
 
diff --git a/usr.bin/netstat/ipsec.c b/usr.bin/netstat/ipsec.c
index d3276bf2761..8aeeacee33f 100644
--- a/usr.bin/netstat/ipsec.c
+++ b/usr.bin/netstat/ipsec.c
@@ -111,8 +111,6 @@ __FBSDID("$FreeBSD$");
 
 #include <stdint.h>
 #include <stdio.h>
-#include <string.h>
-#include <unistd.h>
 #include "netstat.h"
 
 #ifdef IPSEC
diff --git a/usr.bin/netstat/ipx.c b/usr.bin/netstat/ipx.c
index b79a93bba98..adc6cfb5ac8 100644
--- a/usr.bin/netstat/ipx.c
+++ b/usr.bin/netstat/ipx.c
@@ -64,8 +64,6 @@ __FBSDID("$FreeBSD$");
 #define	SANAMES
 #include <netipx/spx_debug.h>
 
-#include <nlist.h>
-#include <errno.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/usr.bin/netstat/main.c b/usr.bin/netstat/main.c
index fec7172ad0c..23593d58ff6 100644
--- a/usr.bin/netstat/main.c
+++ b/usr.bin/netstat/main.c
@@ -60,12 +60,10 @@ __FBSDID("$FreeBSD$");
 
 #include <ctype.h>
 #include <err.h>
-#include <errno.h>
 #include <kvm.h>
 #include <limits.h>
 #include <netdb.h>
 #include <nlist.h>
-#include <paths.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/netstat/mbuf.c b/usr.bin/netstat/mbuf.c
index 7f65701ddf5..47a58c4efa6 100644
--- a/usr.bin/netstat/mbuf.c
+++ b/usr.bin/netstat/mbuf.c
@@ -54,8 +54,6 @@ __FBSDID("$FreeBSD$");
 #include <memstat.h>
 #include <stdint.h>
 #include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
 #include "netstat.h"
 
 /*
diff --git a/usr.bin/netstat/netgraph.c b/usr.bin/netstat/netgraph.c
index c4dd647eb6f..adae25e639d 100644
--- a/usr.bin/netstat/netgraph.c
+++ b/usr.bin/netstat/netgraph.c
@@ -50,11 +50,9 @@ __FBSDID("$FreeBSD$");
 #include <netgraph/ng_socketvar.h>
 
 #include <nlist.h>
-#include <errno.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
-#include <unistd.h>
 #include <err.h>
 #include "netstat.h"
 
diff --git a/usr.bin/netstat/pfkey.c b/usr.bin/netstat/pfkey.c
index 2ab58e91dad..22a64219bb9 100644
--- a/usr.bin/netstat/pfkey.c
+++ b/usr.bin/netstat/pfkey.c
@@ -83,8 +83,6 @@ __FBSDID("$FreeBSD$");
 
 #include <stdint.h>
 #include <stdio.h>
-#include <string.h>
-#include <unistd.h>
 #include "netstat.h"
 
 #ifdef IPSEC
diff --git a/usr.bin/netstat/route.c b/usr.bin/netstat/route.c
index 2e9e919f109..db7a4d117e3 100644
--- a/usr.bin/netstat/route.c
+++ b/usr.bin/netstat/route.c
@@ -69,7 +69,6 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 #include <string.h>
 #include <sysexits.h>
-#include <unistd.h>
 #include <err.h>
 #include "netstat.h"
 
diff --git a/usr.bin/netstat/sctp.c b/usr.bin/netstat/sctp.c
index fe29787ef19..82a4c13cfcc 100644
--- a/usr.bin/netstat/sctp.c
+++ b/usr.bin/netstat/sctp.c
@@ -52,13 +52,10 @@ __FBSDID("$FreeBSD$");
 
 #include <err.h>
 #include <errno.h>
-#include <libutil.h>
-#include <netdb.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 #include "netstat.h"
 
 #ifdef SCTP
diff --git a/usr.bin/newgrp/newgrp.c b/usr.bin/newgrp/newgrp.c
index 91b62a52779..b5e040211f2 100644
--- a/usr.bin/newgrp/newgrp.c
+++ b/usr.bin/newgrp/newgrp.c
@@ -34,10 +34,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 
 #include <err.h>
-#include <errno.h>
 #include <grp.h>
 #include <libgen.h>
-#include <limits.h>
 #include <login_cap.h>
 #include <paths.h>
 #include <pwd.h>
diff --git a/usr.bin/newkey/update.c b/usr.bin/newkey/update.c
index 11a1db94261..eba42fc255f 100644
--- a/usr.bin/newkey/update.c
+++ b/usr.bin/newkey/update.c
@@ -58,7 +58,6 @@ __FBSDID("$FreeBSD$");
 #include <netdb.h>
 #endif	/* YP */
 
-#include <pwd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/usr.bin/nfsstat/nfsstat.c b/usr.bin/nfsstat/nfsstat.c
index 4af133b1370..aa964b83f7e 100644
--- a/usr.bin/nfsstat/nfsstat.c
+++ b/usr.bin/nfsstat/nfsstat.c
@@ -62,7 +62,6 @@ static const char rcsid[] =
 
 #include <signal.h>
 #include <fcntl.h>
-#include <ctype.h>
 #include <errno.h>
 #include <kvm.h>
 #include <limits.h>
@@ -71,7 +70,6 @@ static const char rcsid[] =
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <paths.h>
 #include <err.h>
 
 struct nlist nl[] = {
diff --git a/usr.bin/nohup/nohup.c b/usr.bin/nohup/nohup.c
index 06f22445771..aa3109ceab2 100644
--- a/usr.bin/nohup/nohup.c
+++ b/usr.bin/nohup/nohup.c
@@ -54,7 +54,6 @@ __FBSDID("$FreeBSD$");
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 
 static void dofile(void);
diff --git a/usr.bin/passwd/passwd.c b/usr.bin/passwd/passwd.c
index d35458c956a..dd12a562324 100644
--- a/usr.bin/passwd/passwd.c
+++ b/usr.bin/passwd/passwd.c
@@ -41,7 +41,6 @@ __FBSDID("$FreeBSD$");
 #include <pwd.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <syslog.h>
 #include <unistd.h>
 
 #include <security/pam_appl.h>
diff --git a/usr.bin/paste/paste.c b/usr.bin/paste/paste.c
index 6e3e5539d0c..72c27365aec 100644
--- a/usr.bin/paste/paste.c
+++ b/usr.bin/paste/paste.c
@@ -52,12 +52,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 
 #include <err.h>
-#include <errno.h>
-#include <limits.h>
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 #include <wchar.h>
 
diff --git a/usr.bin/pr/egetopt.c b/usr.bin/pr/egetopt.c
index 277459ee47a..cf42d7c4463 100644
--- a/usr.bin/pr/egetopt.c
+++ b/usr.bin/pr/egetopt.c
@@ -46,11 +46,8 @@ __FBSDID("$FreeBSD$");
 
 #include <ctype.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
-#include "extern.h"
-
 /*
  * egetopt:	get option letter from argument vector (an extended
  *		version of getopt).
diff --git a/usr.bin/procstat/procstat_args.c b/usr.bin/procstat/procstat_args.c
index e5a7acda921..1c132ca540c 100644
--- a/usr.bin/procstat/procstat_args.c
+++ b/usr.bin/procstat/procstat_args.c
@@ -34,7 +34,6 @@
 #include <errno.h>
 #include <limits.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
 #include "procstat.h"
diff --git a/usr.bin/procstat/procstat_basic.c b/usr.bin/procstat/procstat_basic.c
index 277517242a4..00109e787f0 100644
--- a/usr.bin/procstat/procstat_basic.c
+++ b/usr.bin/procstat/procstat_basic.c
@@ -30,7 +30,6 @@
 #include <sys/sysctl.h>
 #include <sys/user.h>
 
-#include <err.h>
 #include <stdio.h>
 #include <string.h>
 
diff --git a/usr.bin/procstat/procstat_files.c b/usr.bin/procstat/procstat_files.c
index debb0e44a20..984dced8929 100644
--- a/usr.bin/procstat/procstat_files.c
+++ b/usr.bin/procstat/procstat_files.c
@@ -36,7 +36,6 @@
 
 #include <arpa/inet.h>
 
-#include <err.h>
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/procstat/procstat_vm.c b/usr.bin/procstat/procstat_vm.c
index 5c965a99076..2d3a666ea42 100644
--- a/usr.bin/procstat/procstat_vm.c
+++ b/usr.bin/procstat/procstat_vm.c
@@ -30,7 +30,6 @@
 #include <sys/sysctl.h>
 #include <sys/user.h>
 
-#include <err.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/rev/rev.c b/usr.bin/rev/rev.c
index 8b38897d2f6..66a7ad23938 100644
--- a/usr.bin/rev/rev.c
+++ b/usr.bin/rev/rev.c
@@ -49,11 +49,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 
 #include <err.h>
-#include <errno.h>
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 #include <wchar.h>
 
diff --git a/usr.bin/rlogin/rlogin.c b/usr.bin/rlogin/rlogin.c
index c279535b649..971de675ec6 100644
--- a/usr.bin/rlogin/rlogin.c
+++ b/usr.bin/rlogin/rlogin.c
@@ -72,9 +72,7 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <libutil.h>
 #include <netdb.h>
-#include <paths.h>
 #include <pwd.h>
 #include <setjmp.h>
 #include <termios.h>
diff --git a/usr.bin/rpcgen/rpc_clntout.c b/usr.bin/rpcgen/rpc_clntout.c
index 713cba11d55..76c9b93cb1f 100644
--- a/usr.bin/rpcgen/rpc_clntout.c
+++ b/usr.bin/rpcgen/rpc_clntout.c
@@ -42,7 +42,6 @@ __FBSDID("$FreeBSD$");
  * Copyright (C) 1987, Sun Microsytsems, Inc.
  */
 #include <stdio.h>
-#include <string.h>
 #include <rpc/types.h>
 #include "rpc_parse.h"
 #include "rpc_scan.h"
diff --git a/usr.bin/rpcgen/rpc_hout.c b/usr.bin/rpcgen/rpc_hout.c
index 70683638360..ce92fe24c13 100644
--- a/usr.bin/rpcgen/rpc_hout.c
+++ b/usr.bin/rpcgen/rpc_hout.c
@@ -42,7 +42,6 @@ __FBSDID("$FreeBSD$");
  * Copyright (C) 1987, Sun Microsystems, Inc.
  */
 #include <stdio.h>
-#include <ctype.h>
 #include "rpc_parse.h"
 #include "rpc_scan.h"
 #include "rpc_util.h"
diff --git a/usr.bin/rpcgen/rpc_tblout.c b/usr.bin/rpcgen/rpc_tblout.c
index f96bdfcbc18..736f857484e 100644
--- a/usr.bin/rpcgen/rpc_tblout.c
+++ b/usr.bin/rpcgen/rpc_tblout.c
@@ -43,7 +43,6 @@ __FBSDID("$FreeBSD$");
  */
 #include <err.h>
 #include <stdio.h>
-#include <string.h>
 #include "rpc_parse.h"
 #include "rpc_scan.h"
 #include "rpc_util.h"
diff --git a/usr.bin/rpcgen/rpc_util.c b/usr.bin/rpcgen/rpc_util.c
index 9d1c85be5f1..40805653546 100644
--- a/usr.bin/rpcgen/rpc_util.c
+++ b/usr.bin/rpcgen/rpc_util.c
@@ -42,7 +42,6 @@ __FBSDID("$FreeBSD$");
  * Copyright (C) 1989, Sun Microsystems, Inc.
  */
 #include <err.h>
-#include <ctype.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/usr.bin/ruptime/ruptime.c b/usr.bin/ruptime/ruptime.c
index 1e3356f6f86..b8672e4e46d 100644
--- a/usr.bin/ruptime/ruptime.c
+++ b/usr.bin/ruptime/ruptime.c
@@ -50,7 +50,6 @@ __FBSDID("$FreeBSD$");
 
 #include <dirent.h>
 #include <err.h>
-#include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/rwall/rwall.c b/usr.bin/rwall/rwall.c
index 042b72f7135..d104bde8dbe 100644
--- a/usr.bin/rwall/rwall.c
+++ b/usr.bin/rwall/rwall.c
@@ -60,7 +60,6 @@ __FBSDID("$FreeBSD$");
 #include <pwd.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <time.h>
 #include <unistd.h>
 
diff --git a/usr.bin/sed/main.c b/usr.bin/sed/main.c
index 1a140b14414..f99c12a4132 100644
--- a/usr.bin/sed/main.c
+++ b/usr.bin/sed/main.c
@@ -51,12 +51,10 @@ static const char sccsid[] = "@(#)main.c	8.2 (Berkeley) 1/3/94";
 
 #include <err.h>
 #include <errno.h>
-#include <fcntl.h>
 #include <libgen.h>
 #include <limits.h>
 #include <locale.h>
 #include <regex.h>
-#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/usr.bin/sed/misc.c b/usr.bin/sed/misc.c
index f3b513784a6..4a7f643e9ba 100644
--- a/usr.bin/sed/misc.c
+++ b/usr.bin/sed/misc.c
@@ -41,14 +41,8 @@ static const char sccsid[] = "@(#)misc.c	8.1 (Berkeley) 6/6/93";
 #include <sys/types.h>
 
 #include <err.h>
-#include <limits.h>
 #include <regex.h>
-#include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
-
-#include "defs.h"
-#include "extern.h"
 
 /*
  * Return a string for a regular expression error passed.  This is overkill,
diff --git a/usr.bin/showmount/showmount.c b/usr.bin/showmount/showmount.c
index 5e67cc1bc7b..0a63a32ed2c 100644
--- a/usr.bin/showmount/showmount.c
+++ b/usr.bin/showmount/showmount.c
@@ -55,7 +55,6 @@ static const char rcsid[] =
 #include <sys/socketvar.h>
 
 #include <err.h>
-#include <netdb.h>
 #include <rpc/rpc.h>
 #include <rpc/pmap_clnt.h>
 #include <rpc/pmap_prot.h>
diff --git a/usr.bin/su/su.c b/usr.bin/su/su.c
index 5dcb24a4064..88a19d9e649 100644
--- a/usr.bin/su/su.c
+++ b/usr.bin/su/su.c
@@ -88,7 +88,6 @@ __FBSDID("$FreeBSD$");
 
 #include <err.h>
 #include <errno.h>
-#include <grp.h>
 #include <login_cap.h>
 #include <paths.h>
 #include <pwd.h>
diff --git a/usr.bin/systat/fetch.c b/usr.bin/systat/fetch.c
index 0edce342e7b..124c3b9763f 100644
--- a/usr.bin/systat/fetch.c
+++ b/usr.bin/systat/fetch.c
@@ -42,7 +42,6 @@ static const char sccsid[] = "@(#)fetch.c	8.1 (Berkeley) 6/6/93";
 #include <sys/types.h>
 #include <sys/sysctl.h>
 
-#include <err.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/usr.bin/systat/icmp.c b/usr.bin/systat/icmp.c
index 2d5f8e4e1ff..acf6b3fca99 100644
--- a/usr.bin/systat/icmp.c
+++ b/usr.bin/systat/icmp.c
@@ -54,9 +54,7 @@ static char sccsid[] = "@(#)mbufs.c	8.1 (Berkeley) 6/6/93";
 #include <netinet/ip_icmp.h>
 #include <netinet/icmp_var.h>
 
-#include <stdlib.h>
 #include <string.h>
-#include <paths.h>
 #include "systat.h"
 #include "extern.h"
 #include "mode.h"
diff --git a/usr.bin/systat/iostat.c b/usr.bin/systat/iostat.c
index 90e1578efeb..d3573af5546 100644
--- a/usr.bin/systat/iostat.c
+++ b/usr.bin/systat/iostat.c
@@ -73,7 +73,6 @@ static const char sccsid[] = "@(#)iostat.c	8.1 (Berkeley) 6/6/93";
 #include <devstat.h>
 #include <err.h>
 #include <nlist.h>
-#include <paths.h>
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/usr.bin/systat/ip.c b/usr.bin/systat/ip.c
index 09143285751..44ed6ac9706 100644
--- a/usr.bin/systat/ip.c
+++ b/usr.bin/systat/ip.c
@@ -55,10 +55,6 @@ static const char sccsid[] = "@(#)mbufs.c	8.1 (Berkeley) 6/6/93";
 #include <netinet/udp.h>
 #include <netinet/udp_var.h>
 
-#include <stdlib.h>
-#include <string.h>
-#include <paths.h>
-
 #include "systat.h"
 #include "extern.h"
 #include "mode.h"
diff --git a/usr.bin/systat/main.c b/usr.bin/systat/main.c
index d092f10fe19..90c6208759d 100644
--- a/usr.bin/systat/main.c
+++ b/usr.bin/systat/main.c
@@ -53,7 +53,6 @@ static const char copyright[] =
 #include <limits.h>
 #include <locale.h>
 #include <nlist.h>
-#include <paths.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/systat/mbufs.c b/usr.bin/systat/mbufs.c
index 37be1ef3d59..9b0d4a8c22c 100644
--- a/usr.bin/systat/mbufs.c
+++ b/usr.bin/systat/mbufs.c
@@ -47,7 +47,6 @@ static const char sccsid[] = "@(#)mbufs.c	8.1 (Berkeley) 6/6/93";
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
-#include <paths.h>
 
 #include "systat.h"
 #include "extern.h"
diff --git a/usr.bin/systat/mode.c b/usr.bin/systat/mode.c
index 5f64e3ec237..745a283ff39 100644
--- a/usr.bin/systat/mode.c
+++ b/usr.bin/systat/mode.c
@@ -60,8 +60,6 @@
 
 __FBSDID("$FreeBSD$");
 
-#include <sys/types.h>
-
 #include "systat.h"
 #include "extern.h"
 #include "mode.h"
diff --git a/usr.bin/systat/netstat.c b/usr.bin/systat/netstat.c
index 14fc4956f34..eb469f3e06b 100644
--- a/usr.bin/systat/netstat.c
+++ b/usr.bin/systat/netstat.c
@@ -74,7 +74,6 @@ static const char sccsid[] = "@(#)netstat.c	8.1 (Berkeley) 6/6/93";
 
 #include <netdb.h>
 #include <nlist.h>
-#include <paths.h>
 #include <stdlib.h>
 #include <string.h>
 
diff --git a/usr.bin/systat/swap.c b/usr.bin/systat/swap.c
index 43df8eb8aa1..dca29b508bf 100644
--- a/usr.bin/systat/swap.c
+++ b/usr.bin/systat/swap.c
@@ -53,7 +53,6 @@ static const char sccsid[] = "@(#)swap.c	8.3 (Berkeley) 4/29/95";
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
-#include <err.h>
 
 #include "systat.h"
 #include "extern.h"
diff --git a/usr.bin/systat/tcp.c b/usr.bin/systat/tcp.c
index b7f7592208c..4a69a4f0e2d 100644
--- a/usr.bin/systat/tcp.c
+++ b/usr.bin/systat/tcp.c
@@ -57,9 +57,7 @@ __FBSDID("$FreeBSD$");
 #include <netinet/tcp_timer.h>
 #include <netinet/tcp_var.h>
 
-#include <stdlib.h>
 #include <string.h>
-#include <paths.h>
 
 #include "systat.h"
 #include "extern.h"
diff --git a/usr.bin/systat/vmstat.c b/usr.bin/systat/vmstat.c
index 742e2f7b4f0..6585d938b26 100644
--- a/usr.bin/systat/vmstat.c
+++ b/usr.bin/systat/vmstat.c
@@ -60,7 +60,6 @@ static const char sccsid[] = "@(#)vmstat.c	8.2 (Berkeley) 1/12/94";
 #include <errno.h>
 #include <langinfo.h>
 #include <nlist.h>
-#include <paths.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/usr.bin/tar/getdate.c b/usr.bin/tar/getdate.c
index 8df1e26fba7..effac4e9d3d 100644
--- a/usr.bin/tar/getdate.c
+++ b/usr.bin/tar/getdate.c
@@ -33,8 +33,6 @@ __FBSDID("$FreeBSD$");
 #endif
 
 #include <ctype.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 #include <time.h>
 
diff --git a/usr.bin/tee/tee.c b/usr.bin/tee/tee.c
index 123a2de69ab..de592c5f2df 100644
--- a/usr.bin/tee/tee.c
+++ b/usr.bin/tee/tee.c
@@ -52,7 +52,6 @@ static const char rcsid[] =
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 
 typedef struct _list {
diff --git a/usr.bin/time/time.c b/usr.bin/time/time.c
index a97ffecce20..d586ba14c57 100644
--- a/usr.bin/time/time.c
+++ b/usr.bin/time/time.c
@@ -59,7 +59,6 @@ static const char rcsid[] =
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
-#include <string.h>
 #include <unistd.h>
 
 static int getstathz(void);
diff --git a/usr.bin/tput/tput.c b/usr.bin/tput/tput.c
index a478d5dcf49..e3b8a37cebb 100644
--- a/usr.bin/tput/tput.c
+++ b/usr.bin/tput/tput.c
@@ -45,8 +45,6 @@ static const char copyright[] =
 static const char sccsid[] = "@(#)tput.c	8.2 (Berkeley) 3/19/94";
 #endif
 
-#include <termios.h>
-
 #include <err.h>
 #include <termcap.h>
 #include <stdio.h>
diff --git a/usr.bin/tr/cmap.c b/usr.bin/tr/cmap.c
index 811040c25e7..8c2ab972d98 100644
--- a/usr.bin/tr/cmap.c
+++ b/usr.bin/tr/cmap.c
@@ -33,10 +33,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <assert.h>
-#include <limits.h>
-#include <stdbool.h>
 #include <stdlib.h>
-#include <wchar.h>
 #include "cmap.h"
 
 static struct cmapnode *cmap_splay(struct cmapnode *, wint_t);
diff --git a/usr.bin/tr/cmap.h b/usr.bin/tr/cmap.h
index 9a81e134678..a7c1a3015f6 100644
--- a/usr.bin/tr/cmap.h
+++ b/usr.bin/tr/cmap.h
@@ -29,7 +29,6 @@
 #ifndef CMAP_H
 #define	CMAP_H
 
-#include <limits.h>
 #include <stdbool.h>
 #include <wchar.h>
 
diff --git a/usr.bin/tr/cset.c b/usr.bin/tr/cset.c
index 1b4212949b6..2535eed2d46 100644
--- a/usr.bin/tr/cset.c
+++ b/usr.bin/tr/cset.c
@@ -33,10 +33,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <assert.h>
-#include <stdbool.h>
 #include <stdlib.h>
-#include <wchar.h>
-#include <wctype.h>
 #include "cset.h"
 
 static struct csnode *	cset_delete(struct csnode *, wchar_t);
diff --git a/usr.bin/tr/cset.h b/usr.bin/tr/cset.h
index ab3eabd3e43..4a8108a2db9 100644
--- a/usr.bin/tr/cset.h
+++ b/usr.bin/tr/cset.h
@@ -30,7 +30,6 @@
 #define	CSET_H
 
 #include <stdbool.h>
-#include <wchar.h>
 #include <wctype.h>
 
 struct csnode {
diff --git a/usr.bin/tr/str.c b/usr.bin/tr/str.c
index 86ae1731ac4..1dee776e06b 100644
--- a/usr.bin/tr/str.c
+++ b/usr.bin/tr/str.c
@@ -44,8 +44,6 @@ static const char sccsid[] = "@(#)str.c	8.2 (Berkeley) 4/28/95";
 #include <ctype.h>
 #include <err.h>
 #include <errno.h>
-#include <stddef.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <wchar.h>
diff --git a/usr.bin/tr/tr.c b/usr.bin/tr/tr.c
index 61195ff4dbb..6db16af0f67 100644
--- a/usr.bin/tr/tr.c
+++ b/usr.bin/tr/tr.c
@@ -47,16 +47,12 @@ static const char sccsid[] = "@(#)tr.c	8.2 (Berkeley) 5/4/95";
 
 #include <sys/types.h>
 
-#include <ctype.h>
 #include <err.h>
-#include <limits.h>
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <wchar.h>
-#include <wctype.h>
 
 #include "cmap.h"
 #include "cset.h"
diff --git a/usr.bin/truss/main.c b/usr.bin/truss/main.c
index d0dd073e632..4036a63904e 100644
--- a/usr.bin/truss/main.c
+++ b/usr.bin/truss/main.c
@@ -47,8 +47,6 @@ __FBSDID("$FreeBSD$");
 
 #include <ctype.h>
 #include <err.h>
-#include <errno.h>
-#include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/truss/setup.c b/usr.bin/truss/setup.c
index 53a6fe17f22..4f79ea30c20 100644
--- a/usr.bin/truss/setup.c
+++ b/usr.bin/truss/setup.c
@@ -43,13 +43,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/wait.h>
 
 #include <err.h>
-#include <errno.h>
-#include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
-#include <time.h>
 #include <unistd.h>
 
 #include <machine/reg.h>
diff --git a/usr.bin/tsort/tsort.c b/usr.bin/tsort/tsort.c
index a01a86c3700..e7c538e1d31 100644
--- a/usr.bin/tsort/tsort.c
+++ b/usr.bin/tsort/tsort.c
@@ -52,7 +52,6 @@ __FBSDID("$FreeBSD$");
 #include <ctype.h>
 #include <db.h>
 #include <err.h>
-#include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/ul/ul.c b/usr.bin/ul/ul.c
index 77559cf254f..725fc25765e 100644
--- a/usr.bin/ul/ul.c
+++ b/usr.bin/ul/ul.c
@@ -53,7 +53,6 @@ static const char rcsid[] =
 #include <termcap.h>
 #include <unistd.h>
 #include <wchar.h>
-#include <wctype.h>
 
 #define	IESC	'\033'
 #define	SO	'\016'
diff --git a/usr.bin/unexpand/unexpand.c b/usr.bin/unexpand/unexpand.c
index d59cd4ef8c7..5009ca1fbfd 100644
--- a/usr.bin/unexpand/unexpand.c
+++ b/usr.bin/unexpand/unexpand.c
@@ -54,10 +54,8 @@ static const char sccsid[] = "@(#)unexpand.c	8.1 (Berkeley) 6/6/93";
 #include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 #include <wchar.h>
-#include <wctype.h>
 
 int	all;
 int	nstops;
diff --git a/usr.bin/usbhidaction/usbhidaction.c b/usr.bin/usbhidaction/usbhidaction.c
index a5e25985260..783909ec38f 100644
--- a/usr.bin/usbhidaction/usbhidaction.c
+++ b/usr.bin/usbhidaction/usbhidaction.c
@@ -50,7 +50,6 @@
 #include <usbhid.h>
 #include <syslog.h>
 #include <signal.h>
-#include <errno.h>
 #include <sys/stat.h>
 
 static int	verbose = 0;
diff --git a/usr.bin/vis/foldit.c b/usr.bin/vis/foldit.c
index 6ad82c2dc2f..fcf60473560 100644
--- a/usr.bin/vis/foldit.c
+++ b/usr.bin/vis/foldit.c
@@ -41,12 +41,8 @@ static const char sccsid[] = "@(#)foldit.c	8.1 (Berkeley) 6/6/93";
 
 #include <stdio.h>
 
-#include "extern.h"
-
 int
-foldit(chunk, col, max)
-	char *chunk;
-	int col, max;
+foldit(char *chunk, int col, int max)
 {
 	char *cp;
 
diff --git a/usr.bin/w/pr_time.c b/usr.bin/w/pr_time.c
index acf6f8c987b..b46fe17189e 100644
--- a/usr.bin/w/pr_time.c
+++ b/usr.bin/w/pr_time.c
@@ -43,7 +43,6 @@ static const char sccsid[] = "@(#)pr_time.c	8.2 (Berkeley) 4/4/94";
 #include <sys/time.h>
 
 #include <stdio.h>
-#include <string.h>
 #include <wchar.h>
 
 #include "extern.h"
diff --git a/usr.bin/w/w.c b/usr.bin/w/w.c
index d35892ed402..23fce288b08 100644
--- a/usr.bin/w/w.c
+++ b/usr.bin/w/w.c
@@ -66,7 +66,6 @@ static const char sccsid[] = "@(#)w.c	8.4 (Berkeley) 4/16/94";
 #include <arpa/inet.h>
 #include <arpa/nameser.h>
 
-#include <ctype.h>
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -82,11 +81,9 @@ static const char sccsid[] = "@(#)w.c	8.4 (Berkeley) 4/16/94";
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <timeconv.h>
 #define	_ULOG_POSIX_NAMES
 #include <ulog.h>
 #include <unistd.h>
-#include <vis.h>
 
 #include "extern.h"
 
diff --git a/usr.bin/wall/ttymsg.c b/usr.bin/wall/ttymsg.c
index a977875942a..bb5c43e7a9c 100644
--- a/usr.bin/wall/ttymsg.c
+++ b/usr.bin/wall/ttymsg.c
@@ -48,7 +48,6 @@ static const char sccsid[] = "@(#)ttymsg.c	8.2 (Berkeley) 11/16/93";
 #include <signal.h>
 #include <stdio.h>
 #include <string.h>
-#include <stdlib.h>
 #include <unistd.h>
 
 #include "ttymsg.h"
diff --git a/usr.bin/who/who.c b/usr.bin/who/who.c
index 5db4f883598..a279d143688 100644
--- a/usr.bin/who/who.c
+++ b/usr.bin/who/who.c
@@ -43,7 +43,6 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
-#include <timeconv.h>
 #define _ULOG_POSIX_NAMES
 #include <ulog.h>
 #include <unistd.h>
diff --git a/usr.bin/xinstall/xinstall.c b/usr.bin/xinstall/xinstall.c
index 49e47c65a36..35f6a60cfb4 100644
--- a/usr.bin/xinstall/xinstall.c
+++ b/usr.bin/xinstall/xinstall.c
@@ -53,7 +53,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/time.h>
 #include <sys/wait.h>
 
-#include <ctype.h>
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -86,16 +85,16 @@ int dobackup, docompare, dodir, dopreserve, dostrip, nommap, safecopy, verbose;
 mode_t mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
 const char *suffix = BACKUP_SUFFIX;
 
-void	copy(int, const char *, int, const char *, off_t);
-int	compare(int, const char *, size_t, int, const char *, size_t);
-int	create_newfile(const char *, int, struct stat *);
-int	create_tempfile(const char *, char *, size_t);
-void	install(const char *, const char *, u_long, u_int);
-void	install_dir(char *);
-u_long	numeric_id(const char *, const char *);
-void	strip(const char *);
-int	trymmap(int);
-void	usage(void);
+static void	copy(int, const char *, int, const char *, off_t);
+static int	compare(int, const char *, size_t, int, const char *, size_t);
+static int	create_newfile(const char *, int, struct stat *);
+static int	create_tempfile(const char *, char *, size_t);
+static void	install(const char *, const char *, u_long, u_int);
+static void	install_dir(char *);
+static u_long	numeric_id(const char *, const char *);
+static void	strip(const char *);
+static int	trymmap(int);
+static void	usage(void);
 
 int
 main(int argc, char *argv[])
diff --git a/usr.bin/ypcat/ypcat.c b/usr.bin/ypcat/ypcat.c
index 3484bc9c1f4..3da854e1fbe 100644
--- a/usr.bin/ypcat/ypcat.c
+++ b/usr.bin/ypcat/ypcat.c
@@ -40,7 +40,6 @@ __FBSDID("$FreeBSD$");
 #include <rpcsvc/yp_prot.h>
 #include <rpcsvc/ypclnt.h>
 
-#include <ctype.h>
 #include <err.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/ypmatch/ypmatch.c b/usr.bin/ypmatch/ypmatch.c
index a9c32ea72c4..707a9e93c2f 100644
--- a/usr.bin/ypmatch/ypmatch.c
+++ b/usr.bin/ypmatch/ypmatch.c
@@ -40,7 +40,6 @@ __FBSDID("$FreeBSD$");
 #include <rpcsvc/yp_prot.h>
 #include <rpcsvc/ypclnt.h>
 
-#include <ctype.h>
 #include <err.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/usr.bin/ypwhich/ypwhich.c b/usr.bin/ypwhich/ypwhich.c
index 4e719dffcd0..cb43f64d30a 100644
--- a/usr.bin/ypwhich/ypwhich.c
+++ b/usr.bin/ypwhich/ypwhich.c
@@ -43,7 +43,6 @@ __FBSDID("$FreeBSD$");
 
 #include <arpa/inet.h>
 
-#include <ctype.h>
 #include <err.h>
 #include <netdb.h>
 #include <stdio.h>