From eb234fbe197a252feb088630cc7ba999bff060d5 Mon Sep 17 00:00:00 2001
From: kn <kn@openbsd.org>
Date: Sun, 28 Jul 2024 10:08:44 +0000
Subject: [PATCH] Support "-u name" to remove variable from environment

OK aisha millert
Feedback jmc
---
 usr.bin/env/env.1 | 12 ++++++++++--
 usr.bin/env/env.c | 10 +++++++---
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/usr.bin/env/env.1 b/usr.bin/env/env.1
index 050a8c6c73f..db35cb73a04 100644
--- a/usr.bin/env/env.1
+++ b/usr.bin/env/env.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: env.1,v 1.20 2015/01/12 21:42:53 deraadt Exp $
+.\"	$OpenBSD: env.1,v 1.21 2024/07/28 10:08:44 kn Exp $
 .\" Copyright (c) 1980, 1990 The Regents of the University of California.
 .\" All rights reserved.
 .\"
@@ -30,7 +30,7 @@
 .\"
 .\"	from: @(#)printenv.1	6.7 (Berkeley) 7/28/91
 .\"
-.Dd $Mdocdate: January 12 2015 $
+.Dd $Mdocdate: July 28 2024 $
 .Dt ENV 1
 .Os
 .Sh NAME
@@ -39,6 +39,7 @@
 .Sh SYNOPSIS
 .Nm env
 .Op Fl i
+.Op Fl u Ar name
 .Oo
 .Ar name Ns = Ns Ar value ...
 .Oc
@@ -66,6 +67,10 @@ The options are as follows:
 Causes
 .Nm
 to completely ignore the environment it inherits.
+.It Fl u Ar name
+Remove
+.Ar name
+from the environment.
 .El
 .Pp
 If no
@@ -121,6 +126,9 @@ The
 utility is compliant with the
 .St -p1003.1-2008
 specification.
+The flag
+.Op Fl u
+is an extension to that specification.
 .Pp
 The historic
 .Fl
diff --git a/usr.bin/env/env.c b/usr.bin/env/env.c
index 08aaa75c695..c1629759baa 100644
--- a/usr.bin/env/env.c
+++ b/usr.bin/env/env.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: env.c,v 1.17 2016/10/28 07:22:59 schwarze Exp $	*/
+/*	$OpenBSD: env.c,v 1.18 2024/07/28 10:08:44 kn Exp $	*/
 
 /*
  * Copyright (c) 1988, 1993, 1994
@@ -49,13 +49,17 @@ main(int argc, char *argv[])
 	if (pledge("stdio exec", NULL) == -1)
 		err(1, "pledge");
 
-	while ((ch = getopt(argc, argv, "i-")) != -1)
+	while ((ch = getopt(argc, argv, "-iu:")) != -1)
 		switch(ch) {
 		case '-':			/* obsolete */
 		case 'i':
 			if ((environ = calloc(1, sizeof(char *))) == NULL)
 				err(126, "calloc");
 			break;
+		case 'u':
+			if (unsetenv(optarg) == -1)
+				err(126, "unsetenv");
+			break;
 		default:
 			usage();
 		}
@@ -91,7 +95,7 @@ usage(void)
 {
 	extern char *__progname;
 
-	(void)fprintf(stderr, "usage: %s [-i] [name=value ...] "
+	(void)fprintf(stderr, "usage: %s [-i] [-u name] [name=value ...] "
 	    "[utility [argument ...]]\n", __progname);
 	exit(1);
 }
-- 
2.20.1