diff --git a/bin/csh/csh.c b/bin/csh/csh.c
index c948f5d70..db411292c 100644
--- a/bin/csh/csh.c
+++ b/bin/csh/csh.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: csh.c,v 1.50 2023/03/08 04:43:04 guenther Exp $	*/
+/*	$OpenBSD: csh.c,v 1.51 2024/07/28 15:31:22 deraadt Exp $	*/
 /*	$NetBSD: csh.c,v 1.14 1995/04/29 23:21:28 mycroft Exp $	*/
 
 /*-
@@ -900,9 +900,7 @@ exitstat(void)
 static void
 phup(int sig)
 {
-    /* XXX sigh, everything after this is a signal race */
-
-    rechist();
+    rechist();	/* XXX big signal race */
 
     /*
      * We kill the last foreground process group. It then becomes
diff --git a/bin/csh/proc.c b/bin/csh/proc.c
index 369e1d699..5451db7a4 100644
--- a/bin/csh/proc.c
+++ b/bin/csh/proc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.c,v 1.35 2023/03/08 04:43:04 guenther Exp $	*/
+/*	$OpenBSD: proc.c,v 1.36 2024/07/28 15:31:22 deraadt Exp $	*/
 /*	$NetBSD: proc.c,v 1.9 1995/04/29 23:21:33 mycroft Exp $	*/
 
 /*-
@@ -207,6 +207,7 @@ pnote(void)
     neednote = 0;
     sigemptyset(&sigset);
     sigaddset(&sigset, SIGCHLD);
+    sigaddset(&sigset, SIGHUP);
     for (pp = proclist.p_next; pp != NULL; pp = pp->p_next) {
 	if (pp->p_flags & PNEEDNOTE) {
 	    sigprocmask(SIG_BLOCK, &sigset, &osigset);
@@ -234,6 +235,7 @@ pwait(void)
      */
     sigemptyset(&sigset);
     sigaddset(&sigset, SIGCHLD);
+    sigaddset(&sigset, SIGHUP);
     sigprocmask(SIG_BLOCK, &sigset, &osigset);
     for (pp = (fp = &proclist)->p_next; pp != NULL; pp = (fp = pp)->p_next)
 	if (pp->p_pid == 0) {
@@ -276,10 +278,12 @@ pjwait(struct process *pp)
     fp = pp;
     sigemptyset(&sigset);
     sigaddset(&sigset, SIGCHLD);
+    sigaddset(&sigset, SIGHUP);
     sigprocmask(SIG_BLOCK, &sigset, &osigset);
     for (;;) {
 	sigemptyset(&sigset);
 	sigaddset(&sigset, SIGCHLD);
+	sigaddset(&sigset, SIGHUP);
 	sigprocmask(SIG_BLOCK, &sigset, NULL);
 	jobflags = 0;
 	do
@@ -289,6 +293,7 @@ pjwait(struct process *pp)
 	    break;
 	sigset = osigset;
 	sigdelset(&sigset, SIGCHLD);
+	sigdelset(&sigset, SIGHUP);
 	sigsuspend(&sigset);
     }
     sigprocmask(SIG_SETMASK, &osigset, NULL);
@@ -352,6 +357,7 @@ dowait(Char **v, struct command *t)
     pjobs++;
     sigemptyset(&sigset);
     sigaddset(&sigset, SIGCHLD);
+    sigaddset(&sigset, SIGHUP);
     sigprocmask(SIG_BLOCK, &sigset, &osigset);
 loop:
     for (pp = proclist.p_next; pp; pp = pp->p_next)
@@ -1004,6 +1010,7 @@ pkill(Char **v, int signum)
 
     sigemptyset(&sigset);
     sigaddset(&sigset, SIGCHLD);
+    sigaddset(&sigset, SIGHUP);
     if (setintr)
 	sigaddset(&sigset, SIGINT);
     sigprocmask(SIG_BLOCK, &sigset, NULL);
@@ -1095,6 +1102,7 @@ pstart(struct process *pp, int foregnd)
 
     sigemptyset(&sigset);
     sigaddset(&sigset, SIGCHLD);
+    sigaddset(&sigset, SIGHUP);
     sigprocmask(SIG_BLOCK, &sigset, &osigset);
     np = pp;
     do {
@@ -1255,10 +1263,11 @@ pfork(struct command *t, int wanttty)
     if (child == 16)
 	stderror(ERR_NESTING, 16);
     /*
-     * Hold SIGCHLD until we have the process installed in our table.
+     * Hold SIGCHLD/SIGHUP until we have the process installed in our table.
      */
     sigemptyset(&sigset);
     sigaddset(&sigset, SIGCHLD);
+    sigaddset(&sigset, SIGHUP);
     sigprocmask(SIG_BLOCK, &sigset, &osigset);
     while ((pid = fork()) == -1)
 	if (setintr == 0)
diff --git a/bin/csh/sem.c b/bin/csh/sem.c
index f9ffff8a0..bb47e8925 100644
--- a/bin/csh/sem.c
+++ b/bin/csh/sem.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sem.c,v 1.23 2019/06/28 13:34:58 deraadt Exp $	*/
+/*	$OpenBSD: sem.c,v 1.24 2024/07/28 15:31:22 deraadt Exp $	*/
 /*	$NetBSD: sem.c,v 1.9 1995/09/27 00:38:50 jtc Exp $	*/
 
 /*-
@@ -196,12 +196,13 @@ execute(struct command *t, int wanttty, int *pipein, int *pipeout)
 		t->t_dflg & (F_REPEAT | F_AMPERSAND) || bifunc) {
 		forked++;
 		/*
-		 * We need to block SIGCHLD here, so that if the process does
+		 * We need to block SIGCHLD/SIGHUP here, so that if the process does
 		 * not die before we can set the process group
 		 */
 		if (wanttty >= 0 && !nosigchld) {
 		    sigemptyset(&sigset);
 		    sigaddset(&sigset, SIGCHLD);
+		    sigaddset(&sigset, SIGHUP);
 		    sigprocmask(SIG_BLOCK, &sigset, &csigset);
 		    nosigchld = 1;
 		}
@@ -231,11 +232,13 @@ execute(struct command *t, int wanttty, int *pipein, int *pipeout)
 		if (wanttty >= 0 && !nosigchld && !noexec) {
 		    sigemptyset(&sigset);
 		    sigaddset(&sigset, SIGCHLD);
+		    sigaddset(&sigset, SIGHUP);
 		    sigprocmask(SIG_BLOCK, &sigset, &csigset);
 		    nosigchld = 1;
 		}
 		sigemptyset(&sigset);
 		sigaddset(&sigset, SIGCHLD);
+		sigaddset(&sigset, SIGHUP);
 		sigaddset(&sigset, SIGINT);
 		sigprocmask(SIG_BLOCK, &sigset, &osigset);
 		ochild = child;
diff --git a/usr.bin/env/env.1 b/usr.bin/env/env.1
index 050a8c6c7..db35cb73a 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 08aaa75c6..c1629759b 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);
 }