脚本名:power.sh
	 
	脚本内容:
	#!/bin/sh
	username3=$1
	file_path=$2
	if [ `id -u` -ne 0 ]; then
	echo "Please re-run `basename $0` as root."
	exit 1
	fi
	# Get existing directory
	while true
	do
	if [ -d $file_path ];then
	break;
	fi
	file_path=${file_path%/*}
	done
	dir_name2=$file_path
	# Judge whether the user exists
	grep "^$username3:" /etc/passwd >/dev/null
	if [ $? -ne 0 ];then
	echo "This user \"$username3\" does not exist."
	exit 4
	fi
	su -l $username3 -c "test -r $dir_name2"
	is_read=$?
	su -l $username3 -c "test -x $dir_name2"
	is_exe=$?
	su -l $username3 -c "test -w $dir_name2"
	is_write=$?
	is_read_int=0
	is_exe_int=0
	is_write_int=0
	if [ $is_read -eq 0 ];then
	is_read_int=100
	fi
	if [ $is_exe -eq 0 ];then
	is_exe_int=1
	fi
	if [ $is_write -eq 0 ];then
	is_write_int=10
	fi
	$result_and
	type let > /dev/null 2>&1
	if [ $? -eq 0 ];then
	let result_and=is_read_int+is_exe_int
	let result_and=result_and+is_write_int
	else
	result_and=`expr $is_read_int + $is_exe_int`
	result_and=`expr $result_and + $is_write_int`
	fi
	exit $result_and
	
	应用:
	 
	sh power.sh user1 /opt/abc
	 
	若返回值为111,则表示用户user1 对目录  /opt/abc具有读写执行权限;
	 
	若返回值为101,则表示用户user1 对目录  /opt/abc具有读执行权限;
	 
	若返回值为10,则表示用户user1 对目录  /opt/abc具有写权限;
	 
	注意:必须以 root 执行 power.sh

