PREUN

/bin/sh

if [ "$1" = 0 ]; then
	umask 022
	grep -v '^/bin/ash$' /etc/shells | grep -v '^/bin/bsh$' > /etc/shells.new
	mv -f /etc/shells.new /etc/shells
fi

POSTIN

/bin/sh

umask 022
if [ ! -f /etc/shells ]; then
	echo "/bin/ash" > /etc/shells
	echo "/bin/bsh" >> /etc/shells
else
	if ! grep -q '^/bin/ash$' /etc/shells ; then
		echo "/bin/ash" >> /etc/shells
	fi
	if ! grep -q '^/bin/bsh$' /etc/shells ; then
		echo "/bin/bsh" >> /etc/shells
	fi
fi