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Path: utzoo!mnetor!seismo!elsie!ado
From: ado@elsie.UUCP (Arthur David Olson)
Newsgroups: net.bugs.4bsd
Subject: 4.[123]BSD grep gives wrong exit status if files are missing (with fix)
Message-ID: <6241@elsie.UUCP>
Date: Mon, 15-Sep-86 16:21:47 EDT
Article-I.D.: elsie.6241
Posted: Mon Sep 15 16:21:47 1986
Date-Received: Mon, 15-Sep-86 21:17:47 EDT
Organization: NIH-LEC, Bethesda, MD
Lines: 68
Keywords: grep exit

Index:	bin/grep Fix

Description:
	The manual page for "grep" says that "Exit status is 0 if any matches
	are found, 1 if none, 2 for syntax errors or inaccessible files."
	But neither non-existent files nor files that cannot be successfully
	read yield an exit status of 2.

Repeat-By:
	Script started on Mon Sep 15 16:13:04 1986
	Warning: no access to tty; thus no job control in this shell...
	% /bin/grep exit frobozz /bin/false
	grep: can't open frobozz
	% echo $status
	2
	% /usr/ucb/grep exit frobozz /bin/false
	Can't open frobozz
	/bin/false:exit 1
	% echo $status
	0
	% 
	script done on Mon Sep 15 16:13:39 1986

Fix:
	Either change the manual page or change grep's performance.
	Here are the changes to the function "execute" in the file "ucbgrep.c"
	for 4.1BSD systems; later versions of BSD require similar changes in
	different files.  As usual, the additions are conditioned on
	"OLDVERSION".

> . . .
> execute(file)
> {
> 	register char *p1, *p2;
> 	register c;
> 	int f;
> 	char *ebp, *cbp;
> 
> 	if (file) {
> 		if ((f = open(file, 0)) < 0) {
> 			fprintf(stderr, "Can't open %s\n", file);
> #ifndef OLDVERSION
> 			exit(2);
> #endif /* !OLDVERSION */
> 		}
> 	} else
> 		f = 0;
> . . .
> 				if ((c = read(f, ibuf, BUFSIZ)) <= 0) {
> 					close(f);
> #ifndef OLDVERSION
> 					if (c < 0) {
> 						(void) fprintf(stderr,
> 							"Error reading %s\n",
> 							(file == 0) ?
> 							"standard input" :
> 							file);
> 						exit(2);
> 					}
> #endif /* !OLDVERSION */
> 					if (cflag) {
> 						if (lflag) {
> . . .
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