shell判斷文件或者文件夾是否存在

#!/bin/sh  
  
myPath="/var/log/httpd/"  
myFile="/var /log/httpd/access.log"  
  
#這里的-x 參數判斷$myPath是否存在並且是否具有可執行權限  
if [ ! -x "$myPath"]; then  
　　mkdir "$myPath"  
fi  

#這里的-d 參數判斷$myPath是否存在  
if [ ! -d "$myPath"]; then  
　　mkdir "$myPath"  
fi  
  
#這里的-f參數判斷$myFile是否存在  
if [ ! -f "$myFile" ]; then  
　　touch "$myFile"  
fi  
  
#其他參數還有-n,-n是判斷一個變量是否是否有值  
if [ ! -n "$myVar" ]; then  
　　echo "$myVar is empty"  
　　exit 0  
fi  
  
#兩個變量判斷是否相等  
if [ "$var1" = "$var2" ]; then  
　　echo '$var1 eq $var2'  
else  
　　echo '$var1 not eq $var2'  
fi  

-f 和-e的區別

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 還是用 -f 這個區別是很大的！