The difference between exec and shell_exec functions in PHP_PHP tutorial

These two functions are both functions for executing Linux commands. The difference is that the return results are different. exec can only get the last line of data, while shell_execu can get all the data. ​

If there are the following files in the script path

-bash-4.1# ll
Total usage 12
-rw-rw-r--. 1 www web 133 July 16 15:00 a.php
-rw-r--r--. 1 lee web 59 February 29 17:05 b.php
-rw-r--r--. 1 lee web 81 March 8 17:00 c.php

First take a look at the explanation of these two functions in the PHP manual:

exec --- execute external program

Syntax: string exec ( string command [, array &output [, int &return_var]] )

Description:

exec() executes the given command command, but it does not output anything. It simply returns the last line from the result of the command. If you need to execute a command and get all the information from the command , you can use the passthru() function.

If the parameter array is given, the specified array will be filled with each line output by the command. Note: If the array already contains some elements, exec() will append it to the end of the array. If you don't want this function to append elements, you can call unset() before passing the array to exec().

exec example

The code is as follows

Copy code

代码如下	复制代码
/**  * exec与shell_exec的区别  * 琼台博客  */ $data = exec('/bin/ls -l'); echo ' '; print_r($data); echo ' '; ?>

/**

* The difference between exec and shell_exec

* Qiongtai Blog

​*/
$data = exec('/bin/ls -l');

echo '

*

* Qiongtai Blog

​ ';

?>

Execution results

代码如下	复制代码
$results = shell_exec ( ' wc -w *.txt ' ) ; echo $results ; ?>

-rw-r--r--. 1 lee web 81 Mar 8 17:00 c.phpshell_exec example

shell_exec()

The shell_exec() command line is really just a variation of the backtick (`) operator. If you've ever written a shell or Perl script, you know that you can capture the output of other commands inside the backtick operator. For example, Listing 1 shows how to use backticks to get the word count for each text (.txt) in the current directory.

代码如下	复制代码
/**  *   * 琼台博客  */ $data = shell_exec('/bin/ls -l'); echo ' '; print_r($data); echo ' '; ?>

in shell_exec() Run the same command in

The code is as follows	Copy code
$results = shell_exec ( ' wc -w *.txt ' ) ; echo $results ; ?>

As you can see in Figure 1, the results obtained are the same as those obtained from the shell script The difference between exec and shell_exec

The code is as follows	Copy code
/***/ $data = shell_exec('/bin/ls -l'); echo ' '; ?>

Execution results

total 12
-rw-rw-r--. 1 www web 139 Jul 16 2012 a.php
-rw-r--r--. 1 lee web 59 Feb 29 17:05 b.php
-rw-r--r--. 1 lee web 81 Mar 8 17:00 c.php So those who usually use the exec function should pay attention. If you need to get all the return information, you should use the shell_exec function. Of course, if the command The execution result only has one line of return information, so it doesn’t matter which one you use

http://www.bkjia.com/PHPjc/445295.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/445295.htmlTechArticleThese two functions are both executing Linux command functions. The difference is that the return results are different. exec can only obtain For the last line of data, shell_execu can obtain all the data. If the script path...