<div>
Place a test in your script as follow:<br />
<br />
a=`ps -ef |grep YOURSCRIPT`<br />
if [ $? -eq 0 ] ; then<br />
echo &quot;this is running now&quot;<br />
exit<br />
fi<br />
<br />
&nbsp; &nbsp;So the script will never run if it find another instance<br />
&nbsp;running.
</div>


Place a test in your script as follow:

a=`ps -ef |grep YOURSCRIPT`
if [ $? -eq 0 ] ; then
echo "this is running now"
exit
fi

   So the script will never run if it find another instance
 running.

<div>
in bira's script you should change the first line for<br />
a=`ps -ef |grep YOURSCRIPT|grep -v grep`<br />
otherwise the script will never run.<br />

</div>


in bira's script you should change the first line for
a=`ps -ef |grep YOURSCRIPT|grep -v grep`
otherwise the script will never run.


<div>
Hey Santunes<br />
<br />
&nbsp; I agree<br />
<br />
&nbsp; &nbsp; Regards
</div>


<div>
<div class="content wysiwyg-content">
I am sort of new to UNIX and don't know much of the commands, there I have this question to ask of you guys. <br />
<br />
I have a unix script that is on a schedule to run every friday at 5pm, and to also run on last day of month at 5pm. &nbsp;There will be cases when the two criterias above are true, therefore causing the same job to run simultaneously. &nbsp;Are there any UNIX statements that would avoid this situation from occuring?<br />
<br />
Thanks much for your help!
</div>
</div>


I am sort of new to UNIX and don't know much of the commands, there I have this question to ask of you guys. 

I have a unix script that is on a schedule to run every friday at 5pm, and to also run on last day of month at 5pm.  There will be cases when the two criterias above are true, therefore causing the same job to run simultaneously.  Are there any UNIX statements that would avoid this situation from occuring?

Thanks much for your help!

Simultaneous Runs

Unix is a multitasking, multi-user computer operating system originally developed in 1969 at Bell Labs. Today, it is a modern OS with many commercial flavors and licensees, including FreeBSD, Hewlett-Packard’s UX, IBM AIX and Apple Mac OS-X. Apart from its command-line interface, most UNIX variations support the standardized X Window System for GUIs, with the exception of the Mac OS, which uses a proprietary system.