Shell 文件测试符例子

下面是一个例子，它使用的所有文件测试操作：

假设一个变量的文件保存现有文件名"/var/www/yiibai/unix/test.sh"，其大小为100字节，读，写和执行权限：

#!/bin/sh

file="/var/www/yiibai/unix/test.sh"

if [ -r $file ]
then
   echo "File has read access"
else
   echo "File does not have read access"
fi

if [ -w $file ]
then
   echo "File has write permission"
else
   echo "File does not have write permission"
fi

if [ -x $file ]
then
   echo "File has execute permission"
else
   echo "File does not have execute permission"
fi

if [ -f $file ]
then
   echo "File is an ordinary file"
else
   echo "This is sepcial file"
fi

if [ -d $file ]
then
   echo "File is a directory"
else
   echo "This is not a directory"
fi

if [ -s $file ]
then
   echo "File size is zero"
else
   echo "File size is not zero"
fi

if [ -e $file ]
then
   echo "File exists"
else
   echo "File does not exist"
fi

这将产生以下输出结果：

File has read access
File has write permission
File has execute permission
File is an ordinary file
This is not a directory
File size is zero
File exists

记下以下几点：

• 运算符和表达式之间必须有空格，例如2+2是不正确的，它应该写成2 + 2。
• if...then...else...fi 语句在下一章节中已经解释的决策声明。