shell判断文件,目录是否存在或者具有权限 

#!/bin/sh 





myPath="/var/log/httpd/" 

myFile="/var /log/httpd/access.log" 





# 这里的-x 参数判断$myPath是否存在并且是否具有可执行权限 

if [ ! -x "$myPath"]; then 

mkdir "$myPath" 

 fi 

 

 # 这里的-d 参数判断$myPath是否存在 

 if [ ! -d "$myPath"]; then 

 mkdir "$myPath" 

 fi 

 

 # 这里的-f参数判断$myFile是否存在 

 if [ ! -f "$myFile" ]; then 

 touch "$myFile" 

 fi 

 

 # 其他参数还有-n,-n是判断一个变量是否是否有值 

 if [ ! -n "$myVar" ]; then 

 echo "$myVar is empty" 

 exit 0 

 fi 

 

 # 两个变量判断是否相等 

 if [ "$var1" = "$var2" ]; then 

 echo '$var1 eq $var2' 

 else 

 echo '$var1 not eq $var2' 

 fi 





-f 和-e的区别 

Conditional Logic on Files 





-a file exists. 

-b file exists and is a block special file. 

-c file exists and is a character special file. 

-d file exists and is a directory. 

-e file exists (just the same as -a). 

-f file exists and is a regular file. 

-g file exists and has its setgid(2) bit set. 

-G file exists and has the same group ID as this process. 

-k file exists and has its sticky bit set. 

-L file exists and is a symbolic link. 

-n string length is not zero. 

-o Named option is set on. 

-O file exists and is owned by the user ID of this process. 

-p file exists and is a first in, first out (FIFO) special file or 

named pipe. 

-r file exists and is readable by the current process. 

-s file exists and has a size greater than zero. 

-S file exists and is a socket. 

-t file descriptor number fildes is open and associated with a 

terminal device. 

-u file exists and has its setuid(2) bit set. 

-w file exists and is writable by the current process. 

-x file exists and is executable by the current process. 

-z string length is zero. 





是用 -s 还是用 -f 这个区别是很大的！