#!/bin/bash
if [ $LOGNAME ① root ] #如果当前用户不是root
②
echo "Must have root privileges to run this program"
exit 1
③
cat ④ EOF #用Here文档输出提示信息
Warning: All jobs in the printer queue will be removed.
Please turn off the printer now. Press Enter when you
are ready to continue. Otherwise press Ctrl-C.
⑤ #Here文档结束