--- conf/postfix-script.orig	2014-06-28 00:05:15.000000000 +1000
+++ conf/postfix-script	2015-02-12 15:38:30.000000000 +1100
@@ -288,7 +288,7 @@
 
 	# Check Postfix mail_owner-owned directory tree owner.
 
-	find `ls -d $queue_directory/* | \
+	find `/bin/ls -d $queue_directory/* | \
 	    egrep '/(saved|incoming|active|defer|deferred|bounce|hold|trace|corrupt|public|private|flush)$'` \
 	    ! \( -type p -o -type s \) ! -user $mail_owner \
 		-exec $WARN not owned by $mail_owner: {} \;