Re: GNU shellery

[maya%netbsd.org@localhost]

On Mon, Oct 02, 2017 at 01:34:26AM +0700, Robert Elz wrote:
>     Date:        Sun, 1 Oct 2017 11:53:05 -0400
>     From:        Thor Lancelot Simon <tls%panix.com@localhost>
>     Message-ID:  <20171001155305.GA27300%panix.com@localhost>
> 
>   | It's low risk (unlike, say, modifying the parser in the shell ;-)),
> 
> Nah - that's easy, no risk at all!
> 
>   | And, frankly, I like the name ("tac")
> 
> So do I, I used to have a tac command, and I miss it.
> 
> coypu - your latest diff still had optind used incorrectly, thoe two optind
> lines should be inside the "if we are tail" { statement-list } after the
> getopt while loop.  The tac case isn't using getopt, and so shouldn't be
> using optind either.
> 
> And I'd code it as "if we are [not]? tac" rather that "if we are tail" (ie:
> strcmp(..., "tac") rather than tail, just in case someone has tail
> linked to some other name ("lastlines" ??) we don't want to break that
> by turning that into tac rather than tail.

I've done this, and added a man page.

Index: Makefile
===================================================================
RCS file: /cvsroot/src/usr.bin/tail/Makefile,v
retrieving revision 1.3
diff -u -r1.3 Makefile
--- Makefile	23 Nov 1994 07:41:55 -0000	1.3
+++ Makefile	1 Oct 2017 19:22:32 -0000
@@ -1,7 +1,10 @@
 #	$NetBSD: Makefile,v 1.3 1994/11/23 07:41:55 jtc Exp $
 #	@(#)Makefile	8.1 (Berkeley) 6/6/93
-
 PROG=	tail
 SRCS=	forward.c misc.c read.c reverse.c tail.c
 
+LINKS=	${BINDIR}/tail ${BINDIR}/tac
+
+MAN=	tail.1 tac.1
+
 .include <bsd.prog.mk>
Index: tac.1
===================================================================
RCS file: tac.1
diff -N tac.1
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ tac.1	1 Oct 2017 19:22:32 -0000
@@ -0,0 +1,54 @@
+.\"	$NetBSD$
+.\"
+.\" Copyright (c) 2017 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Maya Rashish.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\"
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in
+.\"    the documentation and/or other materials provided with the
+.\"    distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+.\" FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+.\" COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
+.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.Dd October 1, 2017
+.Dt TAC 1
+.Os
+.Sh NAME
+.Nm tac
+.Nd display file in reverse
+.Sh SYNOPSIS
+.Nm
+.Op Ar file ...
+.Sh DESCRIPTION
+This displays the contents of each of each of the specified files,
+or of the standard input if no files are specified its standard input,
+in reverse order.
+.Sh EXIT STATUS
+.Ex -std tac
+.Sh COMPATIBILITY
+The
+.Nm
+utility doesn't support any of the options of GNU tac.
+.Sh SEE ALSO
+.Xr cat 1 ,
+.Xr tail 1
Index: tail.1
===================================================================
RCS file: /cvsroot/src/usr.bin/tail/tail.1,v
retrieving revision 1.17
diff -u -r1.17 tail.1
--- tail.1	4 Jul 2017 07:04:50 -0000	1.17
+++ tail.1	1 Oct 2017 19:22:33 -0000
@@ -32,7 +32,7 @@
 .\"
 .\"	@(#)tail.1	8.1 (Berkeley) 6/6/93
 .\"
-.Dd June 15, 2014
+.Dd October 1, 2017
 .Dt TAIL 1
 .Os
 .Sh NAME
@@ -43,7 +43,7 @@
 .Oo
 .Fl f |
 .Fl F |
-.Fl r
+.Fl rqv
 .Oc
 .Oo
 .Fl b Ar number |
@@ -133,12 +133,17 @@
 option is to display all of the input.
 .El
 .Pp
-If more than a single file is specified, each file is preceded by a
+If more than a single file is specified, or the
+.Fl v
+option is used, each file is preceded by a
 header consisting of the string
 .Dq ==> XXX \*[Le]=
 where
 .Dq XXX
 is the name of the file.
+The
+.Fl q
+flag disables the printing of the header in all cases.
 .Sh EXIT STATUS
 .Ex -std tail
 .Sh SEE ALSO
Index: tail.c
===================================================================
RCS file: /cvsroot/src/usr.bin/tail/tail.c,v
retrieving revision 1.17
diff -u -r1.17 tail.c
--- tail.c	31 Jan 2013 23:09:06 -0000	1.17
+++ tail.c	1 Oct 2017 19:22:33 -0000
@@ -67,6 +67,8 @@
 	enum STYLE style;
 	int ch, first;
 	char *p;
+	int qflag = 0;
+	int vflag = 0;
 
 	setprogname(argv[0]);
 	off = 0;
@@ -105,32 +107,48 @@
 
 	obsolete(argv);
 	style = NOTSET;
-	while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1)
-		switch(ch) {
-		case 'F':
-			fflag = 2;
-			break;
-		case 'b':
-			ARG(512, FBYTES, RBYTES);
-			break;
-		case 'c':
-			ARG(1, FBYTES, RBYTES);
-			break;
-		case 'f':
-			fflag = 1;
-			break;
-		case 'n':
-			ARG(1, FLINES, RLINES);
-			break;
-		case 'r':
-			rflag = 1;
-			break;
-		case '?':
-		default:
-			usage();
-		}
-	argc -= optind;
-	argv += optind;
+	if (strcmp(getprogname(), "tac") == 0) {
+		qflag = 1;
+		vflag = 0;
+		rflag = 1;
+		argc -= 1;
+		argv += 1;
+	} else { /* tail */
+		while ((ch = getopt(argc, argv, "Fb:c:fn:rqv")) != -1)
+			switch(ch) {
+			case 'F':
+				fflag = 2;
+				break;
+			case 'b':
+				ARG(512, FBYTES, RBYTES);
+				break;
+			case 'c':
+				ARG(1, FBYTES, RBYTES);
+				break;
+			case 'f':
+				fflag = 1;
+				break;
+			case 'n':
+				ARG(1, FLINES, RLINES);
+				break;
+			case 'r':
+				rflag = 1;
+				break;
+			case 'q':
+				qflag = 1;
+				vflag = 0;
+				break;
+			case 'v':
+				qflag = 0;
+				vflag = 1;
+				break;
+			case '?':
+			default:
+				usage();
+			}
+		argc -= optind;
+		argv += optind;
+	}
 
 	if (fflag && argc > 1)
 		xerrx(1,
@@ -169,7 +187,7 @@
 				ierr();
 				continue;
 			}
-			if (argc > 1) {
+			if (vflag || (qflag == 0 && argc > 1)) {
 				(void)printf("%s==> %s <==\n",
 				    first ? "" : "\n", fname);
 				first = 0;
@@ -299,7 +317,7 @@
 usage(void)
 {
 	(void)fprintf(stderr,
-	    "Usage: %s [-f | -F | -r] [-b # | -c # | -n #] [file ...]\n",
+	    "Usage: %s [-f | -F | -rqv] [-b # | -c # | -n #] [file ...]\n",
 	    getprogname());
 	exit(1);
 }