代码：

#!/bin/bash

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~bin
export PATH

#让使用者输入档名，并且判断是否真的输入字符串

echo -e "please input a filename,I will check the filename's type and permission.\n\n"
read -p "Input a filename:" filename
test  -z ${filename} && echo "You MUST input a filename" && exit 0      #-z，判断是否为空字符串，若为空，则返回true，exit 0 相当于结束语句，即如果匹配此行，语句直接结束

#判断文件是否存在，若不存在则显示消息并结束脚本

test ! -e ${filename} && echo "The filename '${filename}' DO NOT exist"&& exit 0 

#判断文件类型及属性

test -f ${filename} && filetype="regulare file"
test -d ${filename} && filetype="directory"
test -r ${filename} && perm="readable"
test -w ${filename} && perm="${perm} writable"
test -x ${filename} && perm="${perm} executable"

#输出信息

echo "The filename: ${filename} is a ${filetype}"
echo "And the permissions for you are : ${perm}"

 

 

测试结果：

1.正确判断文本类型以及属性：

[ bin]$ sh file_perm.sh 
please input a filename,I will check the filename's type and permission.

Input a filename:read.sh
The filename: read.sh is a regulare file
And the permissions for you are : readable writable executable

2.判断文件不存在：

[ bin]$ sh file_perm.sh 
please input a filename,I will check the filename's type and permission.

Input a filename:a
The filename 'a' DO NOT exist

3.判断使用者未输入字符：

[ bin]$ sh file_perm.sh 
please input a filename,I will check the filename's type and permission.

Input a filename:
You MUST input a filename