diff --git a/bin/date/date.c b/bin/date/date.c
index d879fa6aa5e2..8c42f083ff52 100644
--- a/bin/date/date.c
+++ b/bin/date/date.c
@@ -67,16 +67,14 @@ static const char rcsid[] =
 time_t tval;
 int retval;
 
-static void setthetime __P((const char *, const char *, int, int));
-static void badformat __P((void));
-static void usage __P((void));
+static void setthetime(const char *, const char *, int, int);
+static void badformat(void);
+static void usage(void);
 
-int logwtmp __P((char *, char *, char *));
+int logwtmp(char *, char *, char *);
 
 int
-main(argc, argv)
-	int argc;
-	char **argv;
+main(int argc, char *argv[])
 {
 	struct timezone tz;
 	int ch, rflag;
@@ -182,12 +180,9 @@ main(argc, argv)
 #define	ATOI2(s)	((s) += 2, ((s)[-2] - '0') * 10 + ((s)[-1] - '0'))
 
 void
-setthetime(fmt, p, jflag, nflag)
-	const char *fmt;
-	register const char *p;
-	int jflag, nflag;
+setthetime(const char *fmt, const char *p, int jflag, int nflag)
 {
-	register struct tm *lt;
+	struct tm *lt;
 	struct timeval tv;
 	const char *dot, *t;
 	int century;
@@ -295,14 +290,14 @@ setthetime(fmt, p, jflag, nflag)
 }
 
 static void
-badformat()
+badformat(void)
 {
 	warnx("illegal time format");
 	usage();
 }
 
 static void
-usage()
+usage(void)
 {
 	(void)fprintf(stderr, "%s\n%s\n",
 	    "usage: date [-jnu] [-d dst] [-r seconds] [-t west] "
diff --git a/bin/date/extern.h b/bin/date/extern.h
index 4726eb6a97c3..17b35bbf06a1 100644
--- a/bin/date/extern.h
+++ b/bin/date/extern.h
@@ -34,4 +34,4 @@
  * $FreeBSD$
  */
 
-int	netsettime __P((time_t));
+int	netsettime(time_t);
diff --git a/bin/date/netdate.c b/bin/date/netdate.c
index 8c5f6e97937d..c8bb51acd780 100644
--- a/bin/date/netdate.c
+++ b/bin/date/netdate.c
@@ -68,8 +68,7 @@ extern int retval;
  * Returns 0 on success.  Returns > 0 on failure, setting retval to 2;
  */
 int
-netsettime(tval)
-	time_t tval;
+netsettime(time_t tval)
 {
 	struct timeval tout;
 	struct servent *sp;
diff --git a/bin/dd/args.c b/bin/dd/args.c
index f639e7768b45..96d9e35e5f09 100644
--- a/bin/dd/args.c
+++ b/bin/dd/args.c
@@ -54,25 +54,25 @@ static const char rcsid[] =
 #include "dd.h"
 #include "extern.h"
 
-static int	c_arg __P((const void *, const void *));
-static int	c_conv __P((const void *, const void *));
-static void	f_bs __P((char *));
-static void	f_cbs __P((char *));
-static void	f_conv __P((char *));
-static void	f_count __P((char *));
-static void	f_files __P((char *));
-static void	f_ibs __P((char *));
-static void	f_if __P((char *));
-static void	f_obs __P((char *));
-static void	f_of __P((char *));
-static void	f_seek __P((char *));
-static void	f_skip __P((char *));
-static u_quad_t	get_num __P((const char *));
-static off_t	get_off_t __P((const char *));
+static int	c_arg(const void *, const void *);
+static int	c_conv(const void *, const void *);
+static void	f_bs(char *);
+static void	f_cbs(char *);
+static void	f_conv(char *);
+static void	f_count(char *);
+static void	f_files(char *);
+static void	f_ibs(char *);
+static void	f_if(char *);
+static void	f_obs(char *);
+static void	f_of(char *);
+static void	f_seek(char *);
+static void	f_skip(char *);
+static u_quad_t	get_num(const char *);
+static off_t	get_off_t(const char *);
 
 static const struct arg {
 	const char *name;
-	void (*f) __P((char *));
+	void (*f)(char *);
 	u_int set, noset;
 } args[] = {
 	{ "bs",		f_bs,		C_BS,	 C_BS|C_IBS|C_OBS|C_OSYNC },
@@ -96,8 +96,7 @@ static char *oper;
  * args -- parse JCL syntax of dd.
  */
 void
-jcl(argv)
-	char **argv;
+jcl(char **argv)
 {
 	struct arg *ap, tmp;
 	char *arg;
@@ -173,8 +172,7 @@ jcl(argv)
 }
 
 static int
-c_arg(a, b)
-	const void *a, *b;
+c_arg(const void *a, const void *b)
 {
 
 	return (strcmp(((const struct arg *)a)->name,
@@ -182,8 +180,7 @@ c_arg(a, b)
 }
 
 static void
-f_bs(arg)
-	char *arg;
+f_bs(char *arg)
 {
 	u_quad_t res;
 
@@ -194,8 +191,7 @@ f_bs(arg)
 }
 
 static void
-f_cbs(arg)
-	char *arg;
+f_cbs(char *arg)
 {
 	u_quad_t res;
 
@@ -206,8 +202,7 @@ f_cbs(arg)
 }
 
 static void
-f_count(arg)
-	char *arg;
+f_count(char *arg)
 {
 	u_quad_t res;
 
@@ -221,8 +216,7 @@ f_count(arg)
 }
 
 static void
-f_files(arg)
-	char *arg;
+f_files(char *arg)
 {
 
 	files_cnt = get_num(arg);
@@ -231,8 +225,7 @@ f_files(arg)
 }
 
 static void
-f_ibs(arg)
-	char *arg;
+f_ibs(char *arg)
 {
 	u_quad_t res;
 
@@ -245,16 +238,14 @@ f_ibs(arg)
 }
 
 static void
-f_if(arg)
-	char *arg;
+f_if(char *arg)
 {
 
 	in.name = arg;
 }
 
 static void
-f_obs(arg)
-	char *arg;
+f_obs(char *arg)
 {
 	u_quad_t res;
 
@@ -267,24 +258,21 @@ f_obs(arg)
 }
 
 static void
-f_of(arg)
-	char *arg;
+f_of(char *arg)
 {
 
 	out.name = arg;
 }
 
 static void
-f_seek(arg)
-	char *arg;
+f_seek(char *arg)
 {
 
 	out.offset = get_off_t(arg);
 }
 
 static void
-f_skip(arg)
-	char *arg;
+f_skip(char *arg)
 {
 
 	in.offset = get_off_t(arg);
@@ -314,8 +302,7 @@ static const struct conv {
 };
 
 static void
-f_conv(arg)
-	char *arg;
+f_conv(char *arg)
 {
 	struct conv *cp, tmp;
 
@@ -334,8 +321,7 @@ f_conv(arg)
 }
 
 static int
-c_conv(a, b)
-	const void *a, *b;
+c_conv(const void *a, const void *b)
 {
 
 	return (strcmp(((const struct conv *)a)->name,
@@ -355,8 +341,7 @@ c_conv(a, b)
  *	   the product of the indicated values.
  */
 static u_quad_t
-get_num(val)
-	const char *val;
+get_num(const char *val)
 {
 	u_quad_t num, mult, prevnum;
 	char *expr;
@@ -424,8 +409,7 @@ get_num(val)
  * cast down to an off_t, if possible.
  */
 static off_t
-get_off_t(val)
-	const char *val;
+get_off_t(const char *val)
 {
 	quad_t num, mult, prevnum;
 	char *expr;
diff --git a/bin/dd/conv.c b/bin/dd/conv.c
index 0987a67f081b..5b56c57058d1 100644
--- a/bin/dd/conv.c
+++ b/bin/dd/conv.c
@@ -58,7 +58,7 @@ static const char rcsid[] =
  * Worst case buffer calculation is (ibs + obs - 1).
  */
 void
-def()
+def(void)
 {
 	u_char *inp;
 	const u_char *t;
@@ -87,7 +87,7 @@ def()
 }
 
 void
-def_close()
+def_close(void)
 {
 	/* Just update the count, everything is already in the buffer. */
 	if (in.dbcnt)
@@ -102,7 +102,7 @@ def_close()
  * max out buffer: obs + cbsz
  */
 void
-block()
+block(void)
 {
 	u_char *inp, *outp;
 	const u_char *t;
@@ -188,7 +188,7 @@ block()
 }
 
 void
-block_close()
+block_close(void)
 {
 	/*
 	 * Copy any remaining data into the output buffer and pad to a record.
@@ -215,7 +215,7 @@ block_close()
  * max out buffer: obs + cbsz
  */
 void
-unblock()
+unblock(void)
 {
 	u_char *inp;
 	const u_char *t;
@@ -249,7 +249,7 @@ unblock()
 }
 
 void
-unblock_close()
+unblock_close(void)
 {
 	u_char *t;
 	size_t cnt;
diff --git a/bin/dd/dd.c b/bin/dd/dd.c
index 35d3d3751498..52d41440d2f7 100644
--- a/bin/dd/dd.c
+++ b/bin/dd/dd.c
@@ -69,15 +69,14 @@ static const char rcsid[] =
 #include "dd.h"
 #include "extern.h"
 
-static void dd_close __P((void));
-static void dd_in __P((void));
-int main __P((int, char *[]));
-static void getfdtype __P((IO *));
-static void setup __P((void));
+static void dd_close(void);
+static void dd_in(void);
+static void getfdtype(IO *);
+static void setup(void);
 
 IO	in, out;		/* input/output state */
 STAT	st;			/* statistics */
-void	(*cfunc) __P((void));	/* conversion function */
+void	(*cfunc)(void);		/* conversion function */
 u_quad_t cpy_cnt;		/* # of blocks to copy */
 off_t	pending = 0;		/* pending seek if sparse */
 u_int	ddflags;		/* conversion options */
@@ -86,9 +85,7 @@ quad_t	files_cnt = 1;		/* # of files to copy */
 const	u_char *ctab;		/* conversion table */
 
 int
-main(argc, argv)
-	int argc __unused;
-	char *argv[];
+main(int argc __unused, char *argv[])
 {
 	(void)setlocale(LC_CTYPE, "");
 	jcl(argv);
@@ -107,7 +104,7 @@ main(argc, argv)
 }
 
 static void
-setup()
+setup(void)
 {
 	u_int cnt;
 	struct timeval tv;
@@ -209,8 +206,7 @@ setup()
 }
 
 static void
-getfdtype(io)
-	IO *io;
+getfdtype(IO *io)
 {
 	struct stat sb;
 	int type;
@@ -246,7 +242,7 @@ getfdtype(io)
 }
 
 static void
-dd_in()
+dd_in(void)
 {
 	ssize_t n;
 
@@ -353,7 +349,7 @@ dd_in()
  * is truncated.
  */
 static void
-dd_close()
+dd_close(void)
 {
 	if (cfunc == def)
 		def_close();
@@ -373,8 +369,7 @@ dd_close()
 }
 
 void
-dd_out(force)
-	int force;
+dd_out(int force)
 {
 	u_char *outp;
 	size_t cnt, i, n;
diff --git a/bin/dd/extern.h b/bin/dd/extern.h
index 7f01b8ba21b5..8bbb357cc9a7 100644
--- a/bin/dd/extern.h
+++ b/bin/dd/extern.h
@@ -40,23 +40,23 @@
 
 #include <sys/cdefs.h>
 
-void block __P((void));
-void block_close __P((void));
-void dd_out __P((int));
-void def __P((void));
-void def_close __P((void));
-void jcl __P((char **));
-void pos_in __P((void));
-void pos_out __P((void));
-void summary __P((void));
-void summaryx __P((int));
-void terminate __P((int));
-void unblock __P((void));
-void unblock_close __P((void));
+void block(void);
+void block_close(void);
+void dd_out(int);
+void def(void);
+void def_close(void);
+void jcl(char **);
+void pos_in(void);
+void pos_out(void);
+void summary(void);
+void summaryx(int);
+void terminate(int);
+void unblock(void);
+void unblock_close(void);
 
 extern IO in, out;
 extern STAT st;
-extern void (*cfunc) __P((void));
+extern void (*cfunc)(void);
 extern u_quad_t cpy_cnt;
 extern size_t cbsz;
 extern u_int ddflags;
diff --git a/bin/dd/misc.c b/bin/dd/misc.c
index 654462e7f213..d59d52e3aea5 100644
--- a/bin/dd/misc.c
+++ b/bin/dd/misc.c
@@ -56,7 +56,7 @@ static const char rcsid[] =
 #include "extern.h"
 
 void
-summary()
+summary(void)
 {
 	struct timeval tv;
 	double secs;
@@ -89,8 +89,7 @@ summary()
 
 /* ARGSUSED */
 void
-summaryx(notused)
-	int notused __unused;
+summaryx(int notused __unused)
 {
 	int save_errno = errno;
 
@@ -100,8 +99,7 @@ summaryx(notused)
 
 /* ARGSUSED */
 void
-terminate(sig)
-	int sig;
+terminate(int sig)
 {
 
 	summary();
diff --git a/bin/dd/position.c b/bin/dd/position.c
index 1a9c4b1df9cc..90019e7a02c6 100644
--- a/bin/dd/position.c
+++ b/bin/dd/position.c
@@ -60,7 +60,7 @@ static const char rcsid[] =
  * output.
  */
 void
-pos_in()
+pos_in(void)
 {
 	off_t cnt;
 	int warned;
@@ -123,7 +123,7 @@ pos_in()
 }
 
 void
-pos_out()
+pos_out(void)
 {
 	struct mtop t_op;
 	off_t cnt;
diff --git a/bin/df/df.c b/bin/df/df.c
index f244c26f8767..9ed8442571d0 100644
--- a/bin/df/df.c
+++ b/bin/df/df.c
@@ -96,27 +96,24 @@ typedef enum { NONE, KILO, MEGA, GIGA, TERA, PETA, UNIT_MAX } unit_t;
 
 int unitp [] = { NONE, KILO, MEGA, GIGA, TERA, PETA };
 
-int	  bread __P((off_t, void *, int));
-int	  checkvfsname __P((const char *, char **));
-char	 *getmntpt __P((char *));
-int	  main __P((int, char *[]));
-char	 *makenetvfslist __P((void));
-char	**makevfslist __P((char *));
-void	  prthuman __P((struct statfs *, long));
-void	  prthumanval __P((double));
-void	  prtstat __P((struct statfs *, int));
-long	  regetmntinfo __P((struct statfs **, long, char **));
-int	  ufs_df __P((char *, int));
-unit_t	  unit_adjust __P((double *));
-void	  usage __P((void));
+int	  bread(off_t, void *, int);
+int	  checkvfsname(const char *, char **);
+char	 *getmntpt(char *);
+char	 *makenetvfslist(void);
+char	**makevfslist(char *);
+void	  prthuman(struct statfs *, long);
+void	  prthumanval(double);
+void	  prtstat(struct statfs *, int);
+long	  regetmntinfo(struct statfs **, long, char **);
+int	  ufs_df(char *, int);
+unit_t	  unit_adjust(double *);
+void	  usage(void);
 
 int	aflag = 0, hflag, iflag, nflag;
 struct	ufs_args mdev;
 
 int
-main(argc, argv)
-	int argc;
-	char *argv[];
+main(int argc, char *argv[])
 {
 	struct stat stbuf;
 	struct statfs statfsbuf, *mntbuf;
@@ -269,8 +266,7 @@ main(argc, argv)
 }
 
 char *
-getmntpt(name)
-	char *name;
+getmntpt(char *name)
 {
 	long mntsize, i;
 	struct statfs *mntbuf;
@@ -289,10 +285,7 @@ getmntpt(name)
  * current (not cached) info.  Returns the new count of valid statfs bufs.
  */
 long
-regetmntinfo(mntbufp, mntsize, vfslist)
-	struct statfs **mntbufp;
-	long mntsize;
-	char **vfslist;
+regetmntinfo(struct statfs **mntbufp, long mntsize, char **vfslist)
 {
 	int i, j;
 	struct statfs *mntbuf;
@@ -320,8 +313,7 @@ regetmntinfo(mntbufp, mntsize, vfslist)
  *
  */
 unit_t
-unit_adjust(val)
-	double *val;
+unit_adjust(double *val)
 {
 	double abval;
 	unit_t unit;
@@ -342,9 +334,7 @@ unit_adjust(val)
 }
 
 void
-prthuman(sfsp, used)
-	struct statfs *sfsp;
-	long used;
+prthuman(struct statfs *sfsp, long used)
 {
 
 	prthumanval((double)sfsp->f_blocks * (double)sfsp->f_bsize);
@@ -353,8 +343,7 @@ prthuman(sfsp, used)
 }
 
 void
-prthumanval(bytes)
-	double bytes;
+prthumanval(double bytes)
 {
 
 	unit_t unit;
@@ -380,9 +369,7 @@ prthumanval(bytes)
  * Print out status about a filesystem.
  */
 void
-prtstat(sfsp, maxwidth)
-	struct statfs *sfsp;
-	int maxwidth;
+prtstat(struct statfs *sfsp, int maxwidth)
 {
 	static long blocksize;
 	static int headerlen, timesthrough;
@@ -447,9 +434,7 @@ union {
 int	rfd;
 
 int
-ufs_df(file, maxwidth)
-	char *file;
-	int maxwidth;
+ufs_df(char *file, int maxwidth)
 {
 	struct statfs statfsbuf;
 	struct statfs *sfsp;
@@ -491,10 +476,7 @@ ufs_df(file, maxwidth)
 }
 
 int
-bread(off, buf, cnt)
-	off_t off;
-	void *buf;
-	int cnt;
+bread(off_t off, void *buf, int cnt)
 {
 	ssize_t nr;
 
@@ -510,7 +492,7 @@ bread(off, buf, cnt)
 }
 
 void
-usage()
+usage(void)
 {
 
 	(void)fprintf(stderr,
@@ -519,7 +501,7 @@ usage()
 }
 
 char *
-makenetvfslist()
+makenetvfslist(void)
 {
 	char *str, *strptr, **listptr;
 	int mib[3], maxvfsconf, cnt=0, i;
diff --git a/bin/domainname/domainname.c b/bin/domainname/domainname.c
index 32a86cab6883..fe6d2bf94c99 100644
--- a/bin/domainname/domainname.c
+++ b/bin/domainname/domainname.c
@@ -53,13 +53,10 @@ static const char rcsid[] =
 #include <string.h>
 #include <unistd.h>
 
-int main __P((int, char *[]));
-void usage __P((void));
+static void usage(void);
 
 int
-main(argc,argv)
-	int argc;
-	char *argv[];
+main(int argc, char *argv[])
 {
 	int ch;
 	char domainname[MAXHOSTNAMELEN];
@@ -86,8 +83,8 @@ main(argc,argv)
 	exit(0);
 }
 
-void
-usage()
+static void
+usage(void)
 {
 	(void)fprintf(stderr, "usage: domainname [ypdomain]\n");
 	exit(1);