uniq: Fixup program usage and manpage

Remove -i as it is not required by POSIX.  We'll add it if we
hit scripts that require it.

README

@@ -79,7 +79,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
 =* tty             yes                          none
 =* uname           yes                          none
 #* unexpand        yes                          none
-=  uniq            no                           none
+=  uniq            no                           [infile [outfile]]
 =* unlink          yes                          none
 =  uudecode        no                           -o
 =  uuencode        no                           -m

uniq.1

@@ -6,7 +6,10 @@
 .Nd report or filter out repeated lines in a file
 .Sh SYNOPSIS
 .Nm
-.Op Fl cdu
+.Op Fl c
+.Op Fl d | u
+.Op Fl f Ar fields
+.Op Fl s Ar chars
 .Op Ar file
 .Sh DESCRIPTION
 .Nm
@@ -26,20 +29,12 @@ Prefixes each line with a count of its consecutive occurrences in the input.
 Suppresses non-duplicate lines (thus 'uniq -d' prints only duplicates).
 .It Fl u
 Suppresses non-unique lines (thus 'uniq -u' prints only uniques).
+.It Fl f Ar fields
+Ignore the first
+.Ar fields
+in each input line when doing comparisons.
+.It Fl s Ar chars
+Ignore the first
+.Ar chars
+characters in each input line when doing comparisons.
 .El
-.Sh BUGS
-The original sbase implementation of
-.Nm
-supported multiple input-file arguments as e.g.
-.Xr cat 1
-and
-.Xr grep 1
-do.
-Unfortunately, POSIX uniq treats its second argument (if present) as an
-output filename and clobbers it. Since users and scripts which rely on
-.Nm
-supporting multiple input-file arguments would be at risk of data loss
-if they ever ran into a POSIX-compatible
-.Nm
-, support for multiple input-file arguments was removed from this
-implementation.

uniq.c

@@ -25,7 +25,7 @@ static long prevlinecount = 0;
 static void
 usage(void)
 {
-	eprintf("usage: %s [-cdiu] [input]]\n", argv0);
+	eprintf("usage: %s [-cdufs] [file]\n", argv0);
 }
 
 int
@@ -34,8 +34,6 @@ main(int argc, char *argv[])
 	FILE *fp;
 
 	ARGBEGIN {
-	case 'i':
-		eprintf("not implemented\n");
 	case 'c':
 		countfmt = "%7ld ";
 		break;