linux 判断当前用户是否是root

　　#---------------------------- root user check ---------------------start

　　if [ `id -u` -ne 0 ]; then

　　echo "Please re-run ${this_file} as root."

　　exit 1

　　fi

　　#---------------------------- root user check ---------------------end

　　if [ x"$USER" = x"" ];then

　　if id |grep "^uid=0(root)">/dev/null ;then

　　:

　　else

　　echo "Please rerun `basename $0` as root ."

　　exit 1

　　fi

　　else

　　if [ ! x"$USER" = x"root" ];then

　　echo "Please rerun `basename $0` as root ."

　　exit 1

　　fi

　　fi

　　#=============== check current user start ================

　　if [ ! $USER = root ];then

　　echo "Please rerun this script as root ."

　　exit 1

　　fi

　　#=============== check current user end ================

　　#!/bin/sh

　　if id |grep "^uid=0(root)">/dev/null ;then

　　echo is root

　　else

　　echo not root

　　fi

　　check_user(){

　　if [ $UID -ne 0 ];then

　　echo "Current user is not ROOT."

　　echo "Please rerun the installer as Root user."

　　exit 11

　　fi

　　}