Update cmp(1) manpage to new style and do not allow both -l and -s to be set

cmp.1

@@ -1,25 +1,36 @@
-.TH CMP 1 sbase\-VERSION
+.Dd November 21, 2014
-.SH NAME
+.Dt CMP 1 sbase\-VERSION
-cmp \- compare two files
+.Os
-.SH SYNOPSIS
+.Sh NAME
-.B cmp
+.Nm cmp
-.RB [ \-ls ]
+.Nd compare two files
-.RI file1
+.Sh SYNOPSIS
-.RI file2
+.Nm cmp
-.SH DESCRIPTION
+.Op Fl l | Fl s
-.B cmp
+.Ar file1 file2
-compares two files byte by byte. If the files differ, cmp prints the byte and
+.Sh DESCRIPTION
+.Nm
+compares two files byte by byte. If the files differ,
+.Nm
+prints the byte and
 line number at which the difference occurred.
-.P
+.Pp
-The status code is 0 if the files are identical, and 1 if not.  If an error
+.Sh OPTIONS
-occurred the status code is 2.
+.Bl -tag -width Ds
-.SH OPTIONS
+.It Fl l
-.TP
+Prints the byte number, and the differing bytes (in octal), for each difference.
-.B \-l
+.It Fl s
-prints the byte number, and the differing bytes (in octal), for each difference.
+Prints nothing, only returns status.
-.TP
+.El
-.B \-s
+.Sh EXIT STATUS
-prints nothing, only returns status.
+.Bl -tag -width Ds
-.SH SEE ALSO
+.It 0
-.IR comm (1),
+The files are identical.
-.IR diff (1)
+.It 1
+The files are different.
+.It >1
+An error occured.
+.El
+.Sh SEE ALSO
+.Xr comm 1 ,
+.Xr diff 1

cmp.c

@@ -10,7 +10,7 @@ enum { Same = 0, Diff = 1, Error = 2 };
 static void
 usage(void)
 {
-	enprintf(Error, "usage: %s [-ls] file1 file2\n", argv0);
+	enprintf(Error, "usage: %s [-l | -s] file1 file2\n", argv0);
 }
 
 int
@@ -34,7 +34,7 @@ main(int argc, char *argv[])
 		usage();
 	} ARGEND;
 
-	if (argc != 2)
+	if (argc != 2 || (lflag && sflag))
 		usage();
 
 	if (argv[0][0] == '-' && !argv[0][1])