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  <h1 class="title">cron
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  <h4 id="crontab-with-enhanced-semantics">crontab (with enhanced semantics)</h4>
<p>For performance, the file &quot;crontab&quot; uses single space as field separator. Letters are not suppored currently. So use &quot;1&quot; for &quot;January&quot; and 2 for &quot;Tuesday&quot; etc.</p>
<p>The sixth field in crontab file could be in the format of <a href="../links/index.html#">internal links</a>. Specifically,  &quot;c:&quot; to execute the following commands in termux and &quot;!&quot; to execute commands directly. If the sixth field is not in any of above formats, then the field will appear as the message of alarm clock.</p>
<p>To make crontab more powerful, we changed the semantics as follows:<br>
The day of a command's execution can be specified by two fields — day of month, and day of week. The command will be run when <span style="color:red">both</span> fields matche the current time.</p>
<p>Note (the original crantab semantics):<br>
The day of a command's execution can be specified by two fields — day of month, and day of week. If both fields are restricted (i.e., aren't *), the command will be run when either field matches the current time. For example, &quot;30 4 1,15 * 5&quot; would cause a command to be run at 4:30 am on the 1st and 15th of each month, plus every Friday.</p>
<h5 id="make-crontab-persist-after-os-rebooting">make crontab persist after OS rebooting</h5>
<p>If uweb browser was launched at least once after rebooting, the crontab jobs are scheduled as normal.</p>
<p>To keep crontab take effect without launching uweb browser once:</p>
<ul>
<li>Install the &quot;com.termux.boot&quot; and &quot;com.termux&quot; Apps.</li>
<li>Create an executable file in termux under the folder &quot;~/.termux/boot/&quot; containing the two lines:<br>
#!/data/data/com.termux/files/usr/bin/sh<br>
am broadcast -n info.torapp.uweb/.AlarmReceiver --es uweb.line &quot;&quot;</li>
<li>Launch &quot;com.termux.boot&quot; once.</li>
</ul>
<h4 id="tcron">tcron</h4>
<p>With the option &quot;custom file handling&quot; enabled, &quot;default.rc&quot; runs as shell script at uweb launching time and &quot;default.rc2&quot; runs whenever uweb becomes foreground.</p>
<p>Use tcron (<a href="i:0bhttps://fastly.jsdelivr.net/gh/torappinfo/uwebjs/bin/tcron.tgz">Click to install</a>) with &quot;default.rc&quot; or &quot;default.rc2&quot;.</p>
<p>usage: tcron logfile command hours [timezone delay_sec elsecommand]<br>
execute &quot;command&quot; during time interval once.<br>
where logfile modification time must be updated if &quot;command&quot; runs successfully.</p>
<p>hours: If positive, then each day is divided into multiple intervals (unit: hour), and in each interval, the &quot;command&quot; runs only once.<br>
If  negative, then the unit is minute.<br>
hours could be also in &quot;hh:mm-hh:mm,...&quot; format. Ex. &quot;6:00-8:30,11:00-13:00,5:30-6:30&quot;.<br>
timezone: an integer, default to be &quot;8&quot; for Beijing China (UTC+8). &quot;0&quot; for Greenwich UK (UTC+0).<br>
delay_sec: execute &quot;command&quot; after &quot;delay_sec&quot; seconds.<br>
elsecommand: executed whenever &quot;command&quot; not run.</p>
<p>ex:<br>
set PATH=/system/bin:/data/data/info.torapp.uweb/files/bin<br>
#Empty the folder &quot;baidu&quot; every 30 days.<br>
tcron /sdcard/b &quot;rm -rf /sdcard/baidu/*;toybox touch /sdcard/b&quot; 720</p>
<p><a target="_self" href="i:0hdefault.rc:../searchurl/txt/default.rc">Install example default.rc file for termux</a></p>

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<p>Last Modified: 8 April 2024<br>
fix typos<br>
<pre></pre>
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