diff --git a/tools/build/depend-cleanup.sh b/tools/build/depend-cleanup.sh
--- a/tools/build/depend-cleanup.sh
+++ b/tools/build/depend-cleanup.sh
@@ -17,22 +17,72 @@
 # anyone would try a NO_CLEAN build against an object tree from before the
 # related change.  One year should be sufficient.
 
+set -e
+set -u
+
+warn()
+{
+	echo "$(basename "$0"):" "$@" >&2
+}
+
+err()
+{
+	warn "$@"
+	exit 1
+}
+
+usage()
+{
+	echo "usage: $(basename $0) [-v] [-n] objtop" >&2
+}
+
+VERBOSE=
+PRETEND=
+while getopts vn o; do
+	case "$o" in
+	v)
+		VERBOSE=1
+		;;
+	n)
+		PRETEND=1
+		;;
+	*)
+		usage
+		exit 1
+		;;
+	esac
+done
+shift $((OPTIND-1))
+
+if [ $# -ne 1 ]; then
+	usage
+	exit 1
+fi
+
 OBJTOP=$1
+shift
 if [ ! -d "$OBJTOP" ]; then
-	echo "usage: $(basename $0) objtop" >&2
-	exit 1
+	err "$OBJTOP: Not a directory"
 fi
 
 if [ -z "${MACHINE+set}" ]; then
-	echo "$(basename "$0"): MACHINE not set" >&2
-	exit 1
+	err "MACHINE not set"
 fi
 
 if [ -z "${MACHINE_ARCH+set}" ]; then
-	echo "$(basename "$0"): MACHINE_ARCH not set" >&2
-	exit 1
+	err "MACHINE_ARCH not set"
 fi
 
+run()
+{
+	if [ "$VERBOSE" ]; then
+		echo "$@"
+	fi
+	if ! [ "$PRETEND" ]; then
+		"$@"
+	fi
+}
+
 # $1 directory
 # $2 source filename w/o extension
 # $3 source extension
@@ -40,13 +90,13 @@
 {
 	if egrep -qw "$2\.$3" "$OBJTOP"/$1/.depend.$2.*o 2>/dev/null; then
 		echo "Removing stale dependencies and objects for $2.$3"
-		rm -f \
+		run rm -f \
 		    "$OBJTOP"/$1/.depend.$2.* \
 		    "$OBJTOP"/$1/$2.*o
 	fi
 	if egrep -qw "$2\.$3" "$OBJTOP"/obj-lib32/$1/.depend.$2.*o 2>/dev/null; then
 		echo "Removing 32-bit stale dependencies and objects for $2.$3"
-		rm -f \
+		run rm -f \
 		    "$OBJTOP"/obj-lib32/$1/.depend.$2.* \
 		    "$OBJTOP"/obj-lib32/$1/$2.*o
 	fi
@@ -63,14 +113,14 @@
     egrep -qw "cddl/contrib/opensolaris/lib/libzfs/common/libzfs_changelist.c" \
     "$OBJTOP"/cddl/lib/libzfs/.depend.libzfs_changelist.o; then
 	echo "Removing old ZFS tree"
-	rm -rf "$OBJTOP"/cddl "$OBJTOP"/obj-lib32/cddl
+	run rm -rf "$OBJTOP"/cddl "$OBJTOP"/obj-lib32/cddl
 fi
 
 # 20200916  WARNS bumped, need bootstrapped crunchgen stubs
 if [ -e "$OBJTOP"/rescue/rescue/rescue.c ] && \
     ! grep -q 'crunched_stub_t' "$OBJTOP"/rescue/rescue/rescue.c; then
 	echo "Removing old rescue(8) tree"
-	rm -rf "$OBJTOP"/rescue/rescue
+	run rm -rf "$OBJTOP"/rescue/rescue
 fi
 
 # 20210105  fda7daf06301   pfctl gained its own version of pf_ruleset.c
@@ -78,13 +128,13 @@
     egrep -qw "sys/netpfil/pf/pf_ruleset.c" \
     "$OBJTOP"/sbin/pfctl/.depend.pf_ruleset.o; then
 	echo "Removing old pf_ruleset dependecy file"
-	rm -rf "$OBJTOP"/sbin/pfctl/.depend.pf_ruleset.o
+	run rm -rf "$OBJTOP"/sbin/pfctl/.depend.pf_ruleset.o
 fi
 
 # 20210108  821aa63a0940   non-widechar version of ncurses removed
 if [ -e "$OBJTOP"/lib/ncurses/ncursesw ]; then
 	echo "Removing stale ncurses objects"
-	rm -rf "$OBJTOP"/lib/ncurses "$OBJTOP"/obj-lib32/lib/ncurses
+	run rm -rf "$OBJTOP"/lib/ncurses "$OBJTOP"/obj-lib32/lib/ncurses
 fi
 
 # 20210608  f20893853e8e    move from atomic.S to atomic.c
@@ -96,7 +146,7 @@
 if [ -e "$OBJTOP"/lib/libc++/libc++.ld ] && \
     fgrep -q "/usr/lib/libc++.so" "$OBJTOP"/lib/libc++/libc++.ld; then
 	echo "Removing old libc++ linker script"
-	rm -f "$OBJTOP"/lib/libc++/libc++.ld
+	run rm -f "$OBJTOP"/lib/libc++/libc++.ld
 fi
 
 # 20220326  fbc002cb72d2    move from bcmp.c to bcmp.S
@@ -108,7 +158,7 @@
 if stat "$OBJTOP"/tests/sys/kqueue/libkqueue/*kqtest* \
     "$OBJTOP"/tests/sys/kqueue/libkqueue/.depend.kqtest* >/dev/null 2>&1; then
 	echo "Removing old kqtest"
-	rm -f "$OBJTOP"/tests/sys/kqueue/libkqueue/.depend.* \
+	run rm -f "$OBJTOP"/tests/sys/kqueue/libkqueue/.depend.* \
 	   "$OBJTOP"/tests/sys/kqueue/libkqueue/*
 fi
 
@@ -118,7 +168,7 @@
 # 20230110  bc42155199b5    usr.sbin/zic/zic -> usr.sbin/zic
 if [ -d "$OBJTOP"/usr.sbin/zic/zic ] ; then
 	echo "Removing old zic directory"
-	rm -rf "$OBJTOP"/usr.sbin/zic/zic
+	run rm -rf "$OBJTOP"/usr.sbin/zic/zic
 fi
 
 # 20230208  29c5f8bf9a01    move from mkmakefile.c to mkmakefile.cc
@@ -133,7 +183,7 @@
 # 20230623  b077aed33b7b    OpenSSL 3.0 update
 if [ -f "$OBJTOP"/secure/lib/libcrypto/aria.o ]; then
 	echo "Removing old OpenSSL 1.1.1 tree"
-	rm -rf "$OBJTOP"/secure/lib/libcrypto \
+	run rm -rf "$OBJTOP"/secure/lib/libcrypto \
 	    "$OBJTOP"/secure/lib/libssl \
 	    "$OBJTOP"/obj-lib32/secure/lib/libcrypto \
 	    "$OBJTOP"/obj-lib32/secure/lib/libssl