实现代码一、

#!/bin/sh# 判断文件是否存在# link：www.jb51.net# date：2013/2/28myPath="/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 "$myVar is empty" exit 0fi# 两个变量判断是否相等if [ "$var1" = "$var2" ]; then echo '$var1 eq $var2'else echo '$var1 not eq $var2'fi

实现代码二、

#shell判断文件夹是否存在#如果文件夹不存在，创建文件夹if [ ! -d "/myfolder" ]; then mkdir /myfolderfi#shell判断文件,目录是否存在或者具有权限folder="/var/www/"file="/var/www/log"# -x 参数判断 $folder 是否存在并且是否具有可执行权限if [ ! -x "$folder"]; then mkdir "$folder"fi# -d 参数判断 $folder 是否存在if [ ! -d "$folder"]; then mkdir "$folder"fi# -f 参数判断 $file 是否存在if [ ! -f "$file" ]; then touch "$file"fi# -n 判断一个变量是否有值if [ ! -n "$var" ]; then echo "$var is empty" exit 0fi# 判断两个变量是否相等if [ "$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！