set-x2.0   [plain text]

# $FreeBSD: head/bin/sh/tests/execution/set-x2.0 222882 2011-06-08 21:58:19Z jilles $

key='must contain this'
PS4="$key+ "
{ r=`set -x; { :; } 2>&1 >/dev/null`; } 2>/dev/null
case $r in
*"$key"*) true ;;
*) false ;;
esac