validp=t
case "$thing" in
*"$nl"*) validp=nil ;;
- *) if ! expr >/dev/null "$thing" : "$ckpat\$"; then validp=nil; fi ;;
+ *) if ! expr >/dev/null "Q$thing" : "Q$ckpat\$"; then validp=nil; fi ;;
esac
case $validp in
nil) echo >&2 "$quis: bad $ckwhat \`$thing'"; exit 1 ;;