bin/65649: Add `-u name' option to env(1)

[Jos Backus]

>Number:         65649
>Category:       bin
>Synopsis:       Add `-u name' option to env(1)
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Fri Apr 16 22:00:41 PDT 2004
>Closed-Date:
>Last-Modified:
>Originator:     Jos Backus
>Release:        FreeBSD 5.2-CURRENT i386
>Organization:
CatNook
>Environment:
System: FreeBSD lizzy.catnook.com 5.2-CURRENT FreeBSD 5.2-CURRENT #49: Fri Apr 16 20:26:49 PDT 2004 root at lizzy.catnook.com:/usr/obj/usr/src/sys/LIZZY i386

>Description:

	This patch adds the `-u name' option to env(1). For a rationale of why
	this is useful (besides compatibility with GNU coreutils), see this
	post:

	    http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=b083i6%2486c%241%40news5.svr.pol.co.uk

>How-To-Repeat:
>Fix:

--- env.c.orig	Fri Apr 16 21:16:44 2004
+++ env.c	Fri Apr 16 21:21:25 2004
@@ -64,13 +64,16 @@
 	char *cleanenv[1];
 	int ch;
 
-	while ((ch = getopt(argc, argv, "-i")) != -1)
+	while ((ch = getopt(argc, argv, "-iu:")) != -1)
 		switch(ch) {
 		case '-':
 		case 'i':
 			environ = cleanenv;
 			cleanenv[0] = NULL;
 			break;
+		case 'u':
+			unsetenv(optarg);
+			break;
 		case '?':
 		default:
 			usage();
@@ -90,6 +93,6 @@
 usage(void)
 {
 	(void)fprintf(stderr,
-	    "usage: env [-i] [name=value ...] [utility [argument ...]]\n");
+	    "usage: env [-i] [[-u name] ...] [name=value ...] [utility [argument ...]]\n");
 	exit(1);
 }
--- env.1.orig	Fri Apr 16 21:16:39 2004
+++ env.1	Fri Apr 16 21:41:17 2004
@@ -44,6 +44,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl i
+.Op Fl u Ar name
 .Op Ar name Ns = Ns Ar value ...
 .Op Ar utility Op Ar argument ...
 .Sh DESCRIPTION
@@ -71,6 +72,14 @@
 by
 .Nm
 is ignored completely.
+.It Fl u Ar name
+Execute the
+.Ar utility
+with
+.Ar name
+removed from the environment,
+if it was present in the environment inherited by
+.Nm  .
 .El
 .Pp
 If no utility is specified,
>Release-Note:
>Audit-Trail:
>Unformatted: