watch (command)

<h2 id="syntax">Syntax</h2>
watch [<i>options</i>] <i>command</i> [<i>command options</i>]

<h2 id="example">Example</h2>
watch "<a href="/facts/Ps_(Unix)/WWR5zQkC">ps</a> -e | grep php"

<p>This will generate a list of <a href="/facts/Process_(computing)/Vcq7EnUV">processes</a> every two seconds, filter for all lines that contain the word "php", and display the results on the screen. The output might look something like this:
</p>
Every 2s: ps -e | grep php                             Tue Jan 30 14:56:33 2007

reconst  30028  0.0  0.0  7044 2596 ?        S    Jan23   0:00 vim -r core/html_api.php
cinonet  28009  0.0  0.2 20708 11064 ?       SN   Jan25   0:30 php5.cgi
donoiz   23810  0.0  0.2 22740 10996 ?       SN   Jan27   0:30 php.cgi 43/pdf

<p>The watch command is useful for viewing changes over time, such as repeatedly running the <a href="/facts/Ls/5GsH3v2a">ls</a> -l command to watch a file's size change, or running ps as in the above example to monitor certain processes continuously.
</p>
<h2 id="arguments">Arguments</h2>
<ul><li>-d – Highlights differences between iterations</li>
<li>-h – Displays a help message, then exits</li>
<li>-n <i>secs</i> – Specifies the interval between executions of the command in seconds</li>
<li>-t – Tells watch not to display the header</li>
<li>-v – Prints version information, then exits</li></ul>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/List_of_Unix_commands/EEuIsUx9">List of Unix commands</a></li></ul>
<h2 id="external-links">External links</h2>
<ul><li><a href="https://linux.die.net/man/1/watch">watch(1)</a>: execute a program periodically, showing output fullscreen – <a href="/facts/Linux/9FvCKSTq">Linux</a> User Commands <a href="/facts/Man_page/S2yYjy0J">Manual</a></li>
<li><a href="http://procps.sourceforge.net/">procps</a></li>
<li><a href="https://gitlab.com/procps-ng/procps#tab-readme">procps-ng</a></li></ul>

watch (command) open-in-new

watch (command)