blocks|key|2777830|text|将停止/启动条件放在every_minute_script.php的开头|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2777831|if($condition+==+false)+{
++++exit();
}|code-block|syntax|javascript|2777832|entityMap^0|A|N|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Put your stop/start condition at the start of <code>every_minute_script.php</code>

<pre><code>if($condition == false) {
 exit();
}
</code></pre>

blocks|key|1581070|text|您能在every_minute_script.php的开头放置某种逻辑来检查一个标志，看看它是否应该做什么？这样，它就会旋转起来，然后在没有工作可做的情况下迅速停止。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1581071|还是你的目的太低效了？|1581072|entityMap^0|3|N|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|N|8|@]|D|@]|E|$]]]|I|$]]

Could you place some kind of logic at the beginning of <code>every_minute_script.php</code> that checks a flag to see if it should do anything? That way it could spin up and then just quickly stop if there is no work to do.

Or is that too inefficient for your purposes?

blocks|key|2777871|text|下面是是一个非常酷的教程，用于使用PHP创建这种功能。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2777872|entityMap|0|LINK|mutability|MUTABLE|url|http://net.tutsplus.com/tutorials/php/managing-cron-jobs-with-php-2/^0|0|3|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

<a href="http://net.tutsplus.com/tutorials/php/managing-cron-jobs-with-php-2/" rel="noreferrer">Here's</a> a pretty cool tutorial for creating exactly this kind of functionality with PHP.

blocks|key|2777910|text|与其以编程方式搅乱crontab+(这是微妙且快速的愤怒)，我建议在您的every_minute_script.php中检查一下：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2777911|if+(!file_exists('/your/path/run_every_minute_script'))+{
++exit;
}|code-block|syntax|javascript|2777912|这样，脚本仍将每分钟启动一次，但如果不满足条件(/your/path/run_every_minute_script不存在)，它将立即终止，无需进一步处理。|offset|length|style|CODE|2777913|(当然，您可以替换不同的条件，例如检查数据库的权限等。)|2777914|如果需要邮寄输出，可以使用包装器脚本。Crontab：|2777915|*+*+*+*+*+/your/path/wrapper.sh+>+/dev/null+2>+/dev/null|2777916|然后包装器脚本正常运行，收集其输出和错误，如果这些不是空的，则将它们发送出去(请注意，您也可以在包装器脚本中进行检查；我们没有，因为它依赖于数据库)。|2777917|entityMap^0|0|0|O|Y|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|12|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|14|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

Rather than messing programatically with crontab (which is subtle and quick to anger), I'd suggest making a check inside your every_minute_script.php:

<pre><code>if (!file_exists('/your/path/run_every_minute_script')) {
 exit;
}
</code></pre>

This way, the script will still start every minute, but if the condition isn't met (<code>/your/path/run_every_minute_script</code> doesn't exist), it will terminate immediately without further processing.

(Of course, you can substitute different conditions there, e.g. checking the database for permission etc.)

<hr>

If you need the output mailed, you can use a wrapper script. Crontab:

<pre><code>* * * * * /your/path/wrapper.sh &gt; /dev/null 2&gt; /dev/null
</code></pre>

The wrapper script then runs the job proper, collects its output and errors, and if those aren't empty, mails them out (note that you could also make the check inside the wrapper script; we didn't, as it relied on database).

blocks|key|2777979|text|我做了一些研究和在论坛上找到的，以下信息：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2777980|调用"crontab+-e“，编辑器环境变量设置为php脚本。该脚本可以修改文件，当它退出时，crontab将重新读取文件并进行更新。|blockquote|2777981|所以，我试过一些东西，而且成功了。我将粘贴下面的工作代码：|2777982|#!/usr/bin/php
<?php

$on++=+"*+*+*+*+*+/usr/bin/php+/home/user/every_minute_script.php\n";
$off+=+"#+*+*+*+*+*+/usr/bin/php+/home/user/every_minute_script.php\n";

$param++++=+isset(+$argv[1]+)+?+$argv[1]+:+'';
$filename+=+isset(+$argv[2]+)+?+$argv[2]+:+'';

if+(+$param+==+'activate'+)
{
++++shell_exec(+'export+EDITOR="/home/user/cron.php+on";+crontab+-e'+);
}
elseif(+$param+==+'deactivate'+)
{
++++shell_exec(+'export+EDITOR="/home/user/cron.php+off";+crontab+-e'+);
}
elseif(+in_array(+$param,+array(+'on',+'off'+)+)+)
{
++++if+(+!is_writable(+$filename+)+)
++++++++exit();

++++$crontab+=+file(+$filename+);
++++$key+=+array_search(+$param+==+'on'+?+$off+:+$on,+$crontab+);

++++if+(+$key+===+false+)
++++++++exit();

++++$crontab[$key]+=+$param+==+'on'+?+$on+:+$off;
++++sleep(+1+);
++++file_put_contents(+$filename,+implode(+'',+$crontab+)+);
}

exit();

?>|code-block|syntax|javascript|2777983|实际上，我们有一个名为cron.php的脚本位于/home/user文件夹中，设置为可执行文件(chmod+a%2Bx+cron.php)，并从命令行(PHP)调用。稍后，我将调整它从网络运行，这是我的意图。|style|CODE|2777984|用法：./cron.php+activate启用cronjob，./cron.php+deactivate禁用它。|2777985|脚本正确地设置编辑器环境变量(自动设置)，然后调用crontab+-e，然后调用编辑器(现在是相同的cron.php脚本)，将临时crontab文件位置作为参数传递。然后，找到并更改正确的crontab行，并保存修改后的版本，替换临时文件。当脚本退出时，crontab将更新。|2777986|这正是我想做的，也符合我的需要。|2777987|其他的答案都很好，可能适合不同的需求和场景，我想感谢每一个做出贡献的人。|2777988|entityMap|0|LINK|mutability|MUTABLE|url|http://www.webmasterworld.com/php/3875021.htm^0|8|7|0|0|0|0|0|B|8|O|A|1C|I|0|3|J|W|L|0|P|A|0|0|0^^$0|@$1|2|3|4|5|6|7|17|8|@]|9|@$A|18|B|19|1|1A]]|C|$]]|$1|D|3|E|5|F|7|1B|8|@]|9|@]|C|$]]|$1|G|3|H|5|6|7|1C|8|@]|9|@]|C|$]]|$1|I|3|J|5|K|7|1D|8|@]|9|@]|C|$L|M]]|$1|N|3|O|5|6|7|1E|8|@$A|1F|B|1G|P|Q]|$A|1H|B|1I|P|Q]|$A|1J|B|1K|P|Q]]|9|@]|C|$]]|$1|R|3|S|5|6|7|1L|8|@$A|1M|B|1N|P|Q]|$A|1O|B|1P|P|Q]]|9|@]|C|$]]|$1|T|3|U|5|6|7|1Q|8|@$A|1R|B|1S|P|Q]]|9|@]|C|$]]|$1|V|3|W|5|6|7|1T|8|@]|9|@]|C|$]]|$1|X|3|Y|5|6|7|1U|8|@]|9|@]|C|$]]|$1|Z|3|-4|5|6|7|1V|8|@]|9|@]|C|$]]]|10|$11|$5|12|13|14|C|$15|16]]]]

I did some research and <a href="http://www.webmasterworld.com/php/3875021.htm">found in a forum</a>, the following message:

<blockquote>
 Call "crontab -e" with the EDITOR
 environment variable set to a php
 script. That script can modify the
 file and when it exits crontab will
 re-read the file and update.
</blockquote>

So, I have tried something, and it worked. I will paste the working code below:

<pre><code>#!/usr/bin/php
&lt;?php

$on = "* * * * * /usr/bin/php /home/user/every_minute_script.php\n";
$off = "# * * * * * /usr/bin/php /home/user/every_minute_script.php\n";

$param = isset( $argv[1] ) ? $argv[1] : '';
$filename = isset( $argv[2] ) ? $argv[2] : '';

if ( $param == 'activate' )
{
 shell_exec( 'export EDITOR="/home/user/cron.php on"; crontab -e' );
}
elseif( $param == 'deactivate' )
{
 shell_exec( 'export EDITOR="/home/user/cron.php off"; crontab -e' );
}
elseif( in_array( $param, array( 'on', 'off' ) ) )
{
 if ( !is_writable( $filename ) )
 exit();

 $crontab = file( $filename );
 $key = array_search( $param == 'on' ? $off : $on, $crontab );

 if ( $key === false )
 exit();

 $crontab[$key] = $param == 'on' ? $on : $off;
 sleep( 1 );
 file_put_contents( $filename, implode( '', $crontab ) );
}

exit();

?&gt;
</code></pre>

As it is, we have a single script named <code>cron.php</code> located at <code>/home/user</code> folder, set to be executable (<code>chmod a+x cron.php</code>) and called from the command-line (PHP-CLI). Later I will tweak it to run from the web, which is my intent.

Usage: <code>./cron.php activate</code> to enable the cronjob and <code>./cron.php deactivate</code> to disable it. 

The script sets the EDITOR environment variable properly (to itself) and then calls <code>crontab -e</code>, which on its turn calls the EDITOR (which is now the same cron.php script) passing the temporary crontab file location as an argument. Then, the proper crontab line is found and changed, and the modified version is saved, substituting the temporary file. When the script exits, crontab will update.

This does exactly what I wanted, and fit my needs.

The other answers are nice and may fit different needs and scenarios, and I want to thank everybody who contributed.

If I type <code>crontab -l</code> in the command-line I can see the following line:

<pre><code># * * * * * /usr/bin/php /home/user/every_minute_script.php
</code></pre>

To start this cronjob, I need to edit the file using <code>crontab -e</code> command, remove the comment character at the beginning of the line, save the edited file, and exit the editor.

To stop this cronjob, the same steps, but adding the comment character at the beginning of the line.

I want to achieve exactly the same effect using a PHP script, instead of manually editing the file.

How to start/stop a cronjob using PHP?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

如果我在命令行中键入crontab -l，我可以看到以下行：# * * * * * /usr/bin/php /home/user/every_minute_script.php要启动这个cron作业，我需要使用crontab -e命令编辑文件，删除行首的注释字符，保存编辑的文件，然后退出编辑器。若要停止，请执行相同的...

问如何使用PHP启动/停止cron作业？
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何使用PHP启动/停止cron作业？EN