[src/trunk]: src/usr.bin/env Implement env(1) -u

[kamil <kamil%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5d3348c265e0
branches:  trunk
changeset: 1007155:5d3348c265e0
user:      kamil <kamil%NetBSD.org@localhost>
date:      Sat Feb 08 10:30:22 2020 +0000

description:
Implement env(1) -u

The option '-u name' causes removal of the name environment variable if
it is in the environment.  This is similar to the unset command in sh(1).
The value for name must not include the '=' character.

Add HISTORY section in the man page.

The -u argument is implemented by Linux, FreeBSD and Darwin.
The lack of -u in NetBSD is a cause for a frequent fallout in the LLVM
toolchain test-suite.

diffstat:

 usr.bin/env/env.1 |  36 +++++++++++++++++++++++++++++++++---
 usr.bin/env/env.c |  11 ++++++++---
 2 files changed, 41 insertions(+), 6 deletions(-)

diffs (120 lines):

diff -r c5d3bf1a4662 -r 5d3348c265e0 usr.bin/env/env.1
--- a/usr.bin/env/env.1 Sat Feb 08 09:05:08 2020 +0000
+++ b/usr.bin/env/env.1 Sat Feb 08 10:30:22 2020 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: env.1,v 1.12 2007/06/08 18:20:42 wiz Exp $
+.\"    $NetBSD: env.1,v 1.13 2020/02/08 10:30:22 kamil Exp $
 .\"
 .\" Copyright (c) 1980, 1990 The Regents of the University of California.
 .\" All rights reserved.
@@ -30,9 +30,9 @@
 .\" SUCH DAMAGE.
 .\"
 .\"    from: @(#)printenv.1    6.7 (Berkeley) 7/28/91
-.\"    $NetBSD: env.1,v 1.12 2007/06/08 18:20:42 wiz Exp $
+.\"    $NetBSD: env.1,v 1.13 2020/02/08 10:30:22 kamil Exp $
 .\"
-.Dd June 8, 2007
+.Dd February 8, 2020
 .Dt ENV 1
 .Os
 .Sh NAME
@@ -41,6 +41,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl i
+.Op Fl u Ar name
 .Op Ar name=value ...
 .Oo
 .Ar utility
@@ -66,6 +67,21 @@
 to completely ignore the environment
 it inherits.
 .Pp
+The option
+.Sq Fl u Ar name
+causes removal of the
+.Ar name
+environment variable if it is in the environment.
+This is similar to the
+.Ic unset
+command in
+.Xr sh 1 .
+The value for
+.Ar name
+must not include the
+.Ql =
+character.
+.Pp
 If no
 .Ar utility
 is specified,
@@ -106,6 +122,10 @@
 The historic
 .Fl
 option has been deprecated but is still supported in this implementation.
+.Pp
+The
+.Fl u
+option is a non-standard extension.
 .Sh SEE ALSO
 .Xr execvp 3 ,
 .Xr environ 7
@@ -114,6 +134,16 @@
 .Nm
 utility conforms to
 .St -p1003.2-92 .
+.Sh HISTORY
+The
+.Nm
+command appeared in
+.Bx 4.4 .
+.Pp
+The
+.Fl u
+option first appeared in
+.Nx 10 .
 .Sh BUGS
 .Nm
 doesn't handle commands with equal
diff -r c5d3bf1a4662 -r 5d3348c265e0 usr.bin/env/env.c
--- a/usr.bin/env/env.c Sat Feb 08 09:05:08 2020 +0000
+++ b/usr.bin/env/env.c Sat Feb 08 10:30:22 2020 +0000
@@ -35,7 +35,7 @@
 
 #ifndef lint
 /*static char sccsid[] = "@(#)env.c    8.3 (Berkeley) 4/2/94";*/
-__RCSID("$NetBSD: env.c,v 1.20 2010/11/16 02:53:49 christos Exp $");
+__RCSID("$NetBSD: env.c,v 1.21 2020/02/08 10:30:22 kamil Exp $");
 #endif /* not lint */
 
 #include <err.h>
@@ -60,13 +60,17 @@
        setprogname(*argv);
        (void)setlocale(LC_ALL, "");
 
-       while ((ch = getopt(argc, argv, "-i")) != -1)
+       while ((ch = getopt(argc, argv, "-iu:")) != -1)
                switch((char)ch) {
                case '-':                       /* obsolete */
                case 'i':
                        environ = cleanenv;
                        cleanenv[0] = NULL;
                        break;
+               case 'u':
+                       if (unsetenv(optarg) == -1)
+                               errx(EXIT_FAILURE, "unsetenv %s", optarg);
+                       break;
                case '?':
                default:
                        usage();
@@ -93,7 +97,8 @@
 static void
 usage(void)
 {
-       (void)fprintf(stderr, "Usage: %s [-i] [name=value ...] [command]\n",
+       (void)fprintf(stderr,
+           "Usage: %s [-i] [-u name] [name=value ...] [command]\n",
            getprogname());
        exit(1);
 }