rm -f pleasefail redo passfail [ -e passfail ] || exit 42 PF1=$(cat passfail) touch pleasefail redo passfail 2>/dev/null && exit 43 [ -e passfail ] || exit 44 PF2=$(cat passfail) [ "$PF1" = "$PF2" ] || exit 45 rm -f pleasefail redo passfail || exit 46 PF3=$(cat passfail) [ "$PF1" != "$PF3" ] || exit 47