diff --git a/bin/ignore b/bin/ignore
index 88e31093e..09611b70b 100755
--- a/bin/ignore
+++ b/bin/ignore
@@ -20,7 +20,7 @@
 # non-ksh script for the nmake ignore prefix
 # @(#)ignore (AT&T Research) 1992-08-11
 
-(set -o posix) 2>/dev/null && set -o posix
+(command set -o posix) 2>/dev/null && set -o posix
 modern_export=`v=; export v=ok 2>/dev/null; echo "$v"`
 
 while	:
diff --git a/bin/mamprobe b/bin/mamprobe
index e5166f47d..d3f513fc9 100755
--- a/bin/mamprobe
+++ b/bin/mamprobe
@@ -21,7 +21,7 @@
 # mamprobe - generate MAM cc probe info
 # Glenn Fowler <gsf@research.att.com>
 
-(set -o posix) 2>/dev/null && set -o posix
+(command set -o posix) 2>/dev/null && set -o posix
 
 command=mamprobe
 
diff --git a/bin/package b/bin/package
index 5888df37c..2a3b92ab9 100755
--- a/bin/package
+++ b/bin/package
@@ -24,7 +24,7 @@ USAGE_LICENSE="[-author?Glenn Fowler <gsf@research.att.com>][-copyright?Copyrigh
 
 command=package
 
-(set -o posix) 2>/dev/null && set -o posix
+(command set -o posix) 2>/dev/null && set -o posix
 path=Bad
 case $PATH in
 Bad*)	echo "Cannot be run by zsh in native mode; use a sh symlink to zsh" >&2
diff --git a/bin/silent b/bin/silent
index e3c148eed..77e85333b 100755
--- a/bin/silent
+++ b/bin/silent
@@ -20,7 +20,7 @@
 # non-ksh stub for the nmake silent prefix
 # @(#)silent (AT&T Research) 1992-08-11
 
-(set -o posix) 2>/dev/null && set -o posix
+(command set -o posix) 2>/dev/null && set -o posix
 modern_export=`v=; export v=ok 2>/dev/null; echo "$v"`
 
 while	: