function.exec.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Execute an external program</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.escapeshellcmd.html">escapeshellcmd</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.passthru.html">passthru</a></div> <div class="up"><a href="ref.exec.html">Program execution Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.exec" class="refentry"> <div class="refnamediv"> <h1 class="refname">exec</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">exec</span> — <span class="dc-title">Execute an external program</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">string</span> <span class="methodname"><b><b>exec</b></b></span> ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$command</tt></span> [, <span class="methodparam"><span class="type">array</span> <tt class="parameter reference">&$output</tt></span> [, <span class="methodparam"><span class="type">int</span> <tt class="parameter reference">&$return_var</tt></span> ]] )</div> <p class="para rdfs-comment"> <b>exec()</b> executes the given <i><tt class="parameter">command</tt></i>. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">command</tt></i></span> <dd> <p class="para"> The command that will be executed. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">output</tt></i></span> <dd> <p class="para"> If the <i><tt class="parameter">output</tt></i> argument is present, then the specified array will be filled with every line of output from the command. Trailing whitespace, such as <i>\n</i>, is not included in this array. Note that if the array already contains some elements, <b>exec()</b> will append to the end of the array. If you do not want the function to append elements, call <a href="function.unset.html" class="function">unset()</a> on the array before passing it to <b>exec()</b>. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">return_var</tt></i></span> <dd> <p class="para"> If the <i><tt class="parameter">return_var</tt></i> argument is present along with the <i><tt class="parameter">output</tt></i> argument, then the return status of the executed command will be written to this variable. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> The last line from the result of the command. If you need to execute a command and have all the data from the command passed directly back without any interference, use the <a href="function.passthru.html" class="function">passthru()</a> function. </p> <p class="para"> To get the output of the executed command, be sure to set and use the <i><tt class="parameter">output</tt></i> parameter. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 An <b>exec()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// outputs the username that owns the running php/httpd process<br />// (on a system with the "whoami" executable in the path)<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">exec</span><span style="color: #007700">(</span><span style="color: #DD0000">'whoami'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 notes"> <h3 class="title">Notes</h3> <div class="warning"><b class="warning">Warning</b><p class="para">When allowing user-supplied data to bepassed to this function, use<a href="function.escapeshellarg.html" class="function">escapeshellarg()</a> or <a href="function.escapeshellcmd.html" class="function">escapeshellcmd()</a>to ensure that users cannot trick the system into executing arbitrarycommands.</p></div> <blockquote><p><b class="note">Note</b>: If a program is started with this function,in order for it to continue running in the background, the output of theprogram must be redirected to a file or another output stream. Failing to do sowill cause PHP to hang until the execution of the program ends.<br /></p></blockquote> <blockquote><p><b class="note">Note</b>: <span class="simpara">When<a href="features.safe-mode.html" class="link">safe mode</a> is enabled, you can onlyexecute files within the <a href="features.safe-mode.html#ini.safe-mode-exec-dir" class="link">safe_mode_exec_dir</a>.For practical reasons, it is currently not allowed to have <i>..</i>components in the path to the executable.</span></p></blockquote> <div class="warning"><b class="warning">Warning</b><p class="simpara">With <a href="features.safe-mode.html" class="link">safe mode</a> enabled,the command string is escaped with <a href="function.escapeshellcmd.html" class="function">escapeshellcmd()</a>. Thus, <i>echo y | echo x</i> becomes <i>echo y \| echo x</i>.</p></div> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.system.html" class="function" rel="rdfs-seeAlso">system()</a></li> <li class="member"><a href="function.passthru.html" class="function" rel="rdfs-seeAlso">passthru()</a></li> <li class="member"><a href="function.escapeshellcmd.html" class="function" rel="rdfs-seeAlso">escapeshellcmd()</a></li> <li class="member"><a href="function.pcntl-exec.html" class="function" rel="rdfs-seeAlso">pcntl_exec()</a></li> <li class="member"><a href="language.operators.execution.html" class="link">backtick operator</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.escapeshellcmd.html">escapeshellcmd</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.passthru.html">passthru</a></div> <div class="up"><a href="ref.exec.html">Program execution Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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