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POUser id in perl cron job
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  1. POUser id in perl cron job
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    copied!<p>I have a Perl script which is running as cron job (every minute). Now, I do certain computation and execution in my file. Whenever the job is running, it does not get access to some folders in the file system. </p> <p>For example, I have folder named <code>/opt/tinyos-2.x/apps/</code>. I have kept this folder public (with 777 permission). I change directory to this folder in my Perl script and try to execute files there. But it does not run, instead I get error saying that:</p> <pre><code>make: *** No rule to make target `telosb'. Stop. </code></pre> <p>I can replicate this error whenever I go to that folder and execute files as sudo. </p> <ol> <li><p>So, I am assuming that my cron somehow becomes "root" (I have my cron under the same user as above folder owner). So what should I do with this kind of problem? </p></li> <li><p>I feel that if I can get user who is currently running in that Perl script, I might find it's user id . Could anyone tell me how can I get the user id in my Perl script? After checking at various places, I found this solution to know user id - <code>print $ENV{"LOGNAME"}</code>. Is this the correct way to know the user in Perl script run by cron job ?</p></li> </ol> <p>Here is what I have: I have a user id "abc". </p> <pre><code>abc@mymachine:crontab -e # Edit this file to introduce tasks to be run by cron. # # Each task to run has to be defined through a single line # indicating with different fields when the task will be run # and what command to run for the task # # To define the time you can provide concrete values for # minute (m), hour (h), day of month (dom), month (mon), # and day of week (dow) or use '*' in these fields (for 'any').# # Notice that tasks will be started based on the cron's system # daemon's notion of time and timezones. # # Output of the crontab jobs (including errors) is sent through # email to the user the crontab file belongs to (unless redirected). # # For example, you can run a backup of all your user accounts # at 5 a.m every week with: # 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/ # # For more information see the manual pages of crontab(5) and cron(8) # # m h dom mon dow command * * * * * /usr/bin/perl /var/www/web/myfolder/LoadPrograms.pl &gt;&gt; /var/www/web/log.txt </code></pre> <p>LoadPrograms.pl</p> <pre><code>#!/usr/bin/perl use DBI; use strict; use Thread; use File::Path; $nullPath = "/opt/tinyos-2.x/apps/Null"; chdir($nullPath) or die "cant chnge directory to null directory\n"; my $nullProgramCommand = "make telosb install.1 bsl,/dev/ttyUSB0"; my $output.=`$nullProgramCommand`; print $output; </code></pre> <p>When my job is running in cron, I don't see any output or anything happening. I get mail at user id location /var/mail/abc :</p> <pre><code>Content-Type: text/plain; charset=ANSI_X3.4-1968 X-Cron-Env: &lt;SHELL=/bin/sh&gt; X-Cron-Env: &lt;HOME=/home/abc&gt; X-Cron-Env: &lt;PATH=/usr/bin:/bin&gt; X-Cron-Env: &lt;LOGNAME=abc&gt; make: *** No rule to make target `telosb'. Stop. </code></pre> <p>This means that It is not running my code at the location I mentioned: /opt/tinyos-2.x/apps/Null. </p> <p>Can anybody help me with this ?</p>
 

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