diff --git a/libexec/rc/debug.sh b/libexec/rc/debug.sh
index eea8a011bc09..b098f0b359b5 100755
--- a/libexec/rc/debug.sh
+++ b/libexec/rc/debug.sh
@@ -1,359 +1,378 @@
 :
 # SPDX-License-Identifier: BSD-2-Clause
 
 # NAME:
 #	debug.sh - selectively debug scripts
 #
 # SYNOPSIS:
 #	$_DEBUG_SH . debug.sh
 #	DebugOn [-eo] "tag" ...
 #	DebugOff [-eo] [rc="rc"] "tag" ...
 #	Debugging
+#	DebugAdd "tag"
 #	DebugEcho ...
 #	DebugLog ...
 #	DebugShell "tag" ...
 #	DebugTrace ...
 #	Debug "tag" ...
 #
 #	$DEBUG_SKIP echo skipped when Debug "tag" is true.
 #	$DEBUG_DO echo only done when Debug "tag" is true.
 #
 # DESCRIPTION:
 #	debug.sh provides the following functions to facilitate
 #	flexible run-time tracing of complicated shell scripts.
 #
 #	DebugOn turns tracing on if any "tag" is found in "DEBUG_SH".
 #	It turns tracing off if "!tag" is found in "DEBUG_SH".
 #	It also sets "DEBUG_ON" to the "tag" that caused tracing to be
 #	enabled, or "DEBUG_OFF" if we matched "!tag".
 #	If '-e' option given returns 1 if no "tag" matched.
 #	If the '-o' flag is given, tracing is turned off unless there
 #	was a matched "tag", useful for functions too noisy to tace.
 #
 #	DebugOff turns tracing on if any "tag" matches "DEBUG_OFF" or
 #	off if any "tag" matches "DEBUG_ON". This allows nested
 #	functions to not interfere with each other.
 #
 #	DebugOff accepts but ignores the '-e' and '-o' options.
 #	The optional "rc" value will be returned rather than the
 #	default of 0. Thus if DebugOff is the last operation in a
 #	function, "rc" will be the return code of that function.
 #
+#	DebugAdd allows adding a "tag" to "DEBUG_SH" to influence
+#	later events, possibly in a child process.
+#
 #	DebugEcho is just shorthand for:
 #.nf
 #	$DEBUG_DO echo "$@"
 #.fi
 #
 #	Debugging returns true if tracing is enabled.
 #	It is useful for bounding complex debug actions, rather than
 #	using lots of "DEBUG_DO" lines.
 #
 #	DebugShell runs an interactive shell if any "tag" is found in
 #	"DEBUG_INTERACTIVE", and there is a tty available.
 #	The shell used is defined by "DEBUG_SHELL" or "SHELL" and
 #	defaults to '/bin/sh'.
 #
 #	Debug calls DebugOn and if that does not turn tracing on, it
 #	calls DebugOff to turn it off.
 #
 #	The variables "DEBUG_SKIP" and "DEBUG_DO" are set so as to
 #	enable/disable code that should be skipped/run when debugging
 #	is turned on. "DEBUGGING" is the same as "DEBUG_SKIP" for
 #	backwards compatability.
 #
 #	The use of $_DEBUG_SH is to prevent multiple inclusion, though
 #	it does no harm in this case.
 #
 # BUGS:
 #	Does not work with some versions of ksh.
 #	If a function turns tracing on, ksh turns it off when the
 #	function returns - useless.
 #	PD ksh works ok ;-)
 #
 # AUTHOR:
 #	Simon J. Gerraty <sjg@crufty.net>
 
 # RCSid:
-#	$Id: debug.sh,v 1.40 2024/09/09 20:06:00 sjg Exp $
+#	$Id: debug.sh,v 1.41 2024/10/22 17:57:22 sjg Exp $
 #
 #	@(#) Copyright (c) 1994-2024 Simon J. Gerraty
 #
 #	This file is provided in the hope that it will
 #	be of use.  There is absolutely NO WARRANTY.
 #	Permission to copy, redistribute or otherwise
 #	use this file is hereby granted provided that
 #	the above copyright notice and this notice are
 #	left intact.
 #
 #	Please send copies of changes and bug-fixes to:
 #	sjg@crufty.net
 #
 
 _DEBUG_SH=:
 
 Myname=${Myname:-`basename $0 .sh`}
 
 # We want to use local if we can
 # if isposix-shell.sh has been sourced isPOSIX_SHELL will be set
 # as will local
 case "$local" in
 local|:) ;;
 *)
 	if (echo ${PATH%:*}) > /dev/null 2>&1; then
 		local=local
 	else
 		local=:
 	fi
 	;;
 esac
 
 DEBUGGING=
 DEBUG_DO=:
 DEBUG_SKIP=
 export DEBUGGING DEBUG_DO DEBUG_SKIP
 
 ##
 # _debugOn match first
 #
 # Actually turn on tracing, set $DEBUG_ON=$match
 #
 # If we have included hooks.sh $_HOOKS_SH will be set
 # and if $first (the first arg to DebugOn) is suitable as a variable
 # name we will run ${first}_debugOn_hooks.
 #
 # We disable tracing for hooks_run itself but functions can trace
 # if they want based on DEBUG_DO
 #
 _debugOn() {
 	DEBUG_OFF=
 	DEBUG_DO=
 	DEBUG_SKIP=:
 	DEBUG_X=-x
 	set -x
 	DEBUG_ON=$1
 	case "$_HOOKS_SH,$2" in
 	,*|:,|:,*[${CASE_CLASS_NEG:-!}A-Za-z0-9_]*) ;;
 	*)	# avoid noise from hooks_run
 		set +x
 		hooks_run ${2}_debugOn_hooks
 		set -x
 		;;
 	esac
 }
 
 ##
 # _debugOff match $DEBUG_ON $first
 #
 # Actually turn off tracing, set $DEBUG_OFF=$match
 #
 # If we have included hooks.sh $_HOOKS_SH will be set
 # and if $first (the first arg to DebugOff) is suitable as a variable
 # name we will run ${first}_debugOff_hooks.
 #
 # We do hooks_run after turning off tracing, but before resetting
 # DEBUG_DO so functions can trace if they want
 #
 _debugOff() {
 	DEBUG_OFF=$1
 	set +x
 	case "$_HOOKS_SH,$3" in
 	,*|:,|:,*[${CASE_CLASS_NEG:-!}A-Za-z0-9_]*) ;;
 	*)	hooks_run ${3}_debugOff_hooks;;
 	esac
 	set +x			# just to be sure
 	DEBUG_ON=$2
 	DEBUG_DO=:
 	DEBUG_SKIP=
 	DEBUG_X=
 }
 
+##
+# DebugAdd tag
+#
+# Add tag to DEBUG_SH
+#
+DebugAdd() {
+        DEBUG_SH=${DEBUG_SH:+$DEBUG_SH,}$1
+        export DEBUG_SH
+}
+
+##
+# DebugEcho message
+#
+# Output message if we are debugging
+#
 DebugEcho() {
 	$DEBUG_DO echo "$@"
 }
 
 ##
 # Debugging
 #
 # return 0 if we are debugging.
 #
 Debugging() {
 	test "$DEBUG_SKIP"
 }
 
 ##
 # DebugLog message
 #
 # Outout message with timestamp if we are debugging
 #
 DebugLog() {
 	$DEBUG_SKIP return 0
 	echo `date '+@ %s [%Y-%m-%d %H:%M:%S %Z]'` "$@"
 }
 
 ##
 # DebugTrace message
 #
 # Something hard to miss when wading through huge -x output
 #
 DebugTrace() {
 	$DEBUG_SKIP return 0
 	set +x
 	echo "@ ==================== [ $DEBUG_ON ] ===================="
 	DebugLog "$@"
 	echo "@ ==================== [ $DEBUG_ON ] ===================="
 	set -x
 }
 
 ##
 # DebugOn [-e] [-o] match ...
 #
 # Turn on debugging if any $match is found in $DEBUG_SH.
 #
 DebugOn() {
 	eval ${local:-:} _e _match _off _rc
 	_rc=0			# avoid problems with set -e
 	_off=:
 	while :
 	do
 		case "$1" in
 		-e) _rc=1; shift;; # caller ok with return 1
 		-o) _off=; shift;; # off unless we have a match
 		*) break;;
 		esac
 	done
 	case ",${DEBUG_SH:-$DEBUG}," in
 	,,)	return $_rc;;
 	*,[Dd]ebug,*) ;;
 	*) $DEBUG_DO set +x;;		# reduce the noise
 	esac
 	_match=
 	# if debugging is off because of a !e
 	# don't add 'all' to the On list.
 	case "$_off$DEBUG_OFF" in
 	:)	_e=all;;
 	*)	_e=;;
 	esac
 	for _e in ${*:-$Myname} $_e
 	do
 		: $_e in ,${DEBUG_SH:-$DEBUG},
 		case ",${DEBUG_SH:-$DEBUG}," in
 		*,!$_e,*|*,!$Myname:$_e,*)
 			# only turn it off if it was on
 			_rc=0
 			$DEBUG_DO _debugOff $_e $DEBUG_ON $1
 			break
 			;;
 		*,$_e,*|*,$Myname:$_e,*)
 			# only turn it on if it was off
 			_rc=0
 			_match=$_e
 			$DEBUG_SKIP _debugOn $_e $1
 			break
 			;;
 		esac
 	done
 	if test -z "$_off$_match"; then
 		# off unless explicit match, but
 		# only turn it off if it was on
 		$DEBUG_DO _debugOff $_e $DEBUG_ON $1
 	fi
 	DEBUGGING=$DEBUG_SKIP	# backwards compatability
 	$DEBUG_DO set -x	# back on if needed
 	$DEBUG_DO set -x	# make sure we see it in trace
 	return $_rc
 }
 
 ##
 # DebugOff [-e] [-o] [rc=$?] match ...
 #
 # Only turn debugging off if one of our args was the reason it
 # was turned on.
 #
 # We normally return 0, but caller can pass rc=$? as first arg
 # so that we preserve the status of last statement.
 #
 # The options '-e' and '-o' are ignored, they just make it easier to
 # keep DebugOn and DebugOff lines in sync.
 #
 DebugOff() {
 	eval ${local:-:} _e _rc
 	case ",${DEBUG_SH:-$DEBUG}," in
 	*,[Dd]ebug,*) ;;
 	*) $DEBUG_DO set +x;;		# reduce the noise
 	esac
 	_rc=0			# always happy
 	while :
 	do
 		case "$1" in
 		-[eo]) shift;;	# ignore it
 		rc=*) eval "_$1"; shift;;
 		*) break;;
 		esac
 	done
 	for _e in $*
 	do
 		: $_e==$DEBUG_OFF DEBUG_OFF
 		case "$DEBUG_OFF" in
 		"")	break;;
 		$_e)	_debugOn $DEBUG_ON $1; return $_rc;;
 		esac
 	done
 	for _e in $*
 	do
 		: $_e==$DEBUG_ON DEBUG_ON
 		case "$DEBUG_ON" in
 		"")	break;;
 		$_e)	_debugOff "" "" $1; return $_rc;;
 		esac
 	done
 	DEBUGGING=$DEBUG_SKIP	# backwards compatability
 	$DEBUG_DO set -x	# back on if needed
 	$DEBUG_DO set -x	# make sure we see it in trace
 	return $_rc
 }
 
 _TTY=${_TTY:-`test -t 0 && tty`}; export _TTY
 
 # override this if you like
 _debugShell() {
 	test "x$_TTY" != x || return 0
 	{
 		echo DebugShell "$@"
 		echo "Type 'exit' to continue..."
 	} > $_TTY
 	${DEBUG_SHELL:-${SHELL:-/bin/sh}} < $_TTY > $_TTY 2>&1
 }
 
 # Run an interactive shell if appropriate
 # Note: you can use $DEBUG_SKIP DebugShell ... to skip unless debugOn
 DebugShell() {
 	eval ${local:-:} _e
 	case "$_TTY%${DEBUG_INTERACTIVE}" in
 	*%|%*) return 0;;	# no tty or no spec
 	esac
 	for _e in ${*:-$Myname} all
 	do
 		case ",${DEBUG_INTERACTIVE}," in
 		*,!$_e,*|*,!$Myname:$_e,*)
 			return 0
 			;;
 		*,$_e,*|*,$Myname:$_e,*)
 			# Provide clues as to why/where
 			_debugShell "$_e: $@"
 			return $?
 			;;
 		esac
 	done
 	return 0
 }
 
 # For backwards compatability
 Debug() {
 	case "${DEBUG_SH:-$DEBUG}" in
 	"")	;;
 	*)	DEBUG_ON=${DEBUG_ON:-_Debug}
 		DebugOn -e $* || DebugOff $DEBUG_LAST
 		DEBUGGING=$DEBUG_SKIP
 		;;
 	esac
 }
diff --git a/share/man/man8/debug.sh.8 b/share/man/man8/debug.sh.8
index 2c137ff3fd42..77a1e06cc56a 100644
--- a/share/man/man8/debug.sh.8
+++ b/share/man/man8/debug.sh.8
@@ -1,182 +1,191 @@
 .\" Copyright (c) 1994-2021 Simon J. Gerraty
 .\"
 .\" SPDX-License-Identifier: BSD-2-Clause
 .\"
 .\" This file is provided in the hope that it will
 .\" be of use.  There is absolutely NO WARRANTY.
 .\" Permission to copy, redistribute or otherwise
 .\" use this file is hereby granted provided that
 .\" the above copyright notice and this notice are
 .\" left intact.
 .\"
 .\" Please send copies of changes and bug-fixes to:
 .\" sjg@crufty.net
 .\"
-.Dd January 31, 2024
+.Dd October 22, 2024
 .Dt DEBUG.SH 8
 .Os
 .Sh NAME
 .Nm debug.sh
 .Nd selectively debug scripts
 .Sh SYNOPSIS
 .Bl -item -compact
 .It
 .Ic $_DEBUG_SH .\& Pa debug.sh
 .Pp
 .It
 .Ic DebugOn Oo Fl eo Oc Ar tag ...
 .It
 .Ic DebugOff Oo Fl eo Oc Oo Cm rc= Ns Ar rc Oc Ar tag ...
 .It
 .Ic Debugging
 .It
+.Ic DebugAdd Ar tag
+.It
 .Ic DebugEcho Op Ar message
 .It
 .Ic DebugLog Op Ar message
 .It
 .Ic DebugShell Ar tag ...
 .It
 .Ic DebugTrace Ar message
 .It
 .Ic Debug Ar tag ...
 .El
 .Sh DESCRIPTION
 .Nm
 provides the following functions to facilitate flexible
 run-time tracing of complicated shell scripts.
 .Bl -tag -width 4n
 .It Ic DebugOn Oo Fl eo Oc Ar tag ...
 turns tracing on if any
 .Ar tag
 is found in
 .Va DEBUG_SH
 (a comma separated list of tags).
 .Pp
 It turns tracing off if
 .Ar !tag
 is found in
 .Va DEBUG_SH .
 .Pp
 It sets
 .Va DEBUG_ON
 to the
 .Ar tag
 that caused tracing to be enabled, or
 .Va DEBUG_OFF
 if we matched
 .Ar !tag .
 .Pp
 If
 .Fl e
 option is present, returns 1 if no
 .Ar tag
 matched.
 .Pp
 If
 .Fl o
 option is present, tracing is turned off unless there
 was a matched
 .Ar tag ,
 useful for functions too noisy to tace.
 .It Ic DebugOff Oo Fl eo Oc Oo Cm rc= Ns Ar rc Oc Ar tag ...
 turns tracing on if any
 .Ar tag
 matches
 .Va DEBUG_OFF
 or off if any
 .Ar tag
 matches
 .Va DEBUG_ON .
 This allows nested functions to not interfere with each other.
 .Pp
 The flags
 .Fl e
 and
 .Fl o
 are ignored, they just allow for symmetry with calls to
 .Fn DebugOn .
 .Pp
 The optional
 .Ar rc
 value will be returned rather than the default of 0.
 Thus if 
 .Fn DebugOff
 is the last operation in a function,
 .Ar rc
 will be the return code of the function.
 .It Ic Debugging
 returns true if tracing is enabled.
 It is useful for bounding complex debug actions, rather than
 using lots of
 .Ic $DEBUG_DO
 lines.
+.It Ic DebugAdd Ar tag
+Add
+.Ar tag
+to
+.Va DEBUG_SH
+to influence later output,
+possibly in a child process.
 .It Ic DebugEcho
 is just shorthand for:
 .Bd -literal -offset indent
 $DEBUG_DO echo "$@"
 .Ed
 .It Ic DebugLog Op Ar message
 If debugging is enabled, output
 .Ar message
 prefixed with a time-stamp.
 .It Ic DebugShell Ar tag ...
 runs an interactive shell if any
 .Ar tag
 is found in
 .Va DEBUG_INTERACTIVE ,
 and there is a tty available.
 The shell used is defined by
 .Va DEBUG_SHELL
 or
 .Va SHELL
 and defaults to
 .Pa /bin/sh .
 .It Ic DebugTrace Ar message
 Debug output can be very noisy, and it can be tricky
 to align with the script.
 This function outputs a very noticable banner indicating the value of
 .Va DEBUG_ON ,
 and
 .Ar message
 is passed to
 .Fn DebugLog ,
 finally the banner is repeated.
 .It Ic Debug Ar tag ...
 For backwards compatibility, calls
 .Fn DebugOn
 and if that does not turn tracing on,
 it calls
 .Fn DebugOff
 to turn it off.
 .El
 .Pp
 The variables
 .Va DEBUG_SKIP
 and
 .Va DEBUG_DO
 are set so as to enable/disable code that should be
 skipped/run when debugging is turned on.
 .Va DEBUGGING
 is the same as
 .Va DEBUG_SKIP
 for backwards compatability and is only set by
 .Fn Debug .
 .Pp
 The use of
 .Ic $_DEBUG_SH
 is to prevent multiple inclusion,
 though it does no harm in this case.
 .Sh BUGS
 Does not work with some versions of
 .Xr ksh 1 .
 If a function turns tracing on, ksh turns it off when the
 function returns - useless.
 .Pp
 PD ksh works ok ;-)
 .Sh AUTHOR
 .An -nosplit
 .Nm
 was written by
 .An Simon J Gerraty Aq Mt sjg@crufty.net .