chgrp: Update program usage and manpage

-h is incompatible with -R so handle that properly as well.

chgrp.1

@@ -6,12 +6,13 @@
 .Nd change the file group ownership
 .Sh SYNOPSIS
 .Nm
-.Op Fl R
-.Op Fl H
-.Op Fl L
-.Op Fl P
-.Ar groupname
-.Op Ar file...
+.Op Fl h
+.Oo
+.Fl R
+.Op Fl H | L | P
+.Oc
+.Ar group
+.Ar file...
 .Sh DESCRIPTION
 .Nm
 sets the group id of the files specified by
@@ -20,6 +21,10 @@ to the gid of the group named
 .Ar group .
 .Sh OPTIONS
 .Bl -tag -width Ds
+.It Fl h
+Change the group ID of the symlink itself.  This flag cannot be used
+with
+.Op Fl R .
 .It Fl R
 Change file group ownership recursively.
 .It Fl H
@@ -42,4 +47,4 @@ The
 .Nm
 utility is compliant with the
 .St -p1003.1-2008
-specification except from the -h flag.
+specification.

chgrp.c

@@ -9,7 +9,7 @@
 
 static int gid;
 static int status;
-static int rflag;
+static int Rflag;
 static int fflag = 'P';
 static struct stat st;
 static char *chown_f_name = "chown";
@@ -22,14 +22,14 @@ chgrp(const char *path, int fflag)
 		weprintf("%s %s:", chown_f_name, path);
 		status = 1;
 	}
-	if (rflag)
+	if (Rflag)
 		recurse(path, chgrp, fflag);
 }
 
 static void
 usage(void)
 {
-	eprintf("usage: chgrp [-hR] groupname file...\n");
+	eprintf("usage: chgrp [-h] [-R [-H | -L | -P]] group file ...\n");
 }
 
 int
@@ -43,7 +43,7 @@ main(int argc, char *argv[])
 		chown_f = lchown;
 		break;
 	case 'R':
-		rflag = 1;
+		Rflag = 1;
 		break;
 	case 'H':
 	case 'L':
@@ -54,7 +54,7 @@ main(int argc, char *argv[])
 		usage();
 	} ARGEND;
 
-	if (argc < 2)
+	if (argc < 2 || (chown_f == lchown && Rflag))
 		usage();
 
 	errno = 0;