shell 判断文件的读写权限和存在 test命令

wangshumin@machine2:~$ 
wangshumin@machine2:~$ vim  test
wangshumin@machine2:~$ sh test
not exit
wangshumin@machine2:~$ sh test
not exit
wangshumin@machine2:~$ sh test
not exit
wangshumin@machine2:~$ cat test
#!/bin/bash


filename=/home/zhangsan
test -f $filename && echo "exit"|| echo "not exit"
wangshumin@machine2:~$ pwd
/home/wangshumin
wangshumin@machine2:~$ cd /home/
wangshumin@machine2:/home$ touch zhangsan
touch: 无法创建'zhangsan': 权限不够
wangshumin@machine2:/home$ sudo touch zhangsan
[sudo] wangshumin 的密码： 
wangshumin@machine2:/home$ pwd
/home
wangshumin@machine2:/home$ ls
wangshumin  zhangsan
wangshumin@machine2:/home$ sh test
sh: 0: Can't open test
wangshumin@machine2:/home$ cd 
wangshumin@machine2:~$ sh test
exit
wangshumin@machine2:~$ vim  test 
wangshumin@machine2:~$ sh test
exit
not exit
exitr
not exit
not exit
wangshumin@machine2:~$ cd  /home/
wangshumin@machine2:/home$ ls
wangshumin  zhangsan
wangshumin@machine2:/home$ ll
总用量 12
drwxr-xr-x  3 root       root       4096 3月   9 16:54 ./
drwxr-xr-x 24 root       root       4096 3月   7 15:28 ../
drwxr-xr-x 20 wangshumin wangshumin 4096 3月   9 16:56 wangshumin/
-rw-r--r--  1 root       root          0 3月   9 16:54 zhangsan
wangshumin@machine2:/home$ cat  test
cat: test: 没有那个文件或目录
wangshumin@machine2:/home$ cd
wangshumin@machine2:~$ cat  test
#!/bin/bash


filename=/home/zhangsan
test -f $filename && echo "exit"|| echo "not exit"
test -d $filename && echo "exitd"|| echo "not exit"
test -r $filename && echo "exitr"|| echo "not exit"
test -w $filename && echo "exitw"|| echo "not exit"
test -x $filename && echo "exitx"|| echo "not exit"





wangshumin@machine2:~$ [10=10] &&echo  'yes'|| echo  "no"
1：未找到命令
no
wangshumin@machine2:~$ [ 10 = 10 ]  && echo  'yes'|| echo  "no"
yes
wangshumin@machine2:~$ 
wangshumin@machine2:~$ 
wangshumin@machine2:~$ 
wangshumin@machine2:~$ [ 10 = 13 ]  && echo  'yes'|| echo  "no"
no
wangshumin@machine2:~$ [ '10' = 13 ]  && echo  'yes'|| echo  "no"
no
wangshumin@machine2:~$ [ 10 = '10' ]  && echo  'yes'|| echo  "no"
yes
wangshumin@machine2:~$ [ '10' = 13 ]  && echo  'yes'|| echo  "no"
no
wangshumin@machine2:~$ vim test2
wangshumin@machine2:~$ sh test2
no 
wangshumin@machine2:~$ vim test2
wangshumin@machine2:~$ sh test2
test2: 6: [: this: unexpected operator
no 
wangshumin@machine2:~$ vim test2
wangshumin@machine2:~$ sh test2
yes 
wangshumin@machine2:~$ cat   test2
#!/bin/bash
a=this
b=this




[ $a = $b ] && echo  "yes "|| echo  "no "
wangshumin@machine2:~$