Shell 檔測試符例子

下麵是一個例子，它使用的所有檔測試操作：

假設一個變數的檔保存現有檔案名"/var/www/zaixian/unix/test.sh"，其大小為100位元組，讀，寫和執行許可權：

#!/bin/sh

file="/var/www/zaixian/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

這將產生以下輸出結果：

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

記下以下幾點：

• 運算符和運算式之間必須有空格，例如2+2是不正確的，它應該寫成2 + 2。

• if...then...else...fi 語句在下一章節中已經解釋的決策聲明。