linux怎样判断指定用户对指定目录具有的权限具体介绍

#!/bin/sh
username3=$1
dir_name2=$2
# get existing directory
file_path=$dir_name2
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
#echo "username : $username3"
group4=` grep "^$username3:" /etc/passwd |awk -F : {'print $4'}|xargs -i grep {} /etc/group|cut -d":" -f1`
#echo "group : $group4"
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_str
$is_exe_str
$is_write_str
if [ $is_read -eq 0 ];then
is_read_str="r"
else
is_read_str="-"
fi
if [ $is_exe -eq 0 ];then
is_exe_str="x"
else
is_exe_str="-"
fi
if [ $is_write -eq 0 ];then
is_write_str="w"
else
is_write_str="-"
fi
echo "${is_read_str}${is_write_str}${is_exe_str}"