crontab - Deleting individual cron jobs using PHP -

i have php script sets cron job once data inserted sql database:

<? $output = shell_exec('crontab -l'); file_put_contents('/tmp/crontab.txt', $output.'* * * * * /usr/local/bin/php /home/dldl1330/public_html/new/mailchimp.php'.php_eol); echo exec('crontab /tmp/crontab.txt'); ?> 

this cron job executes script syncs sql db mailchimp. in mailchimp php script deletes cron tab:

echo exec('crontab -r'); 

once happens loose jobs in cron tab (and removes email gets emailed after every cron job), how can make above line deletes /home/dldl1330/public_html/new/mailchimp.php cron job?

i used above advise , came solution, not sure how efficient or correct is.... welcome comments.

note: //find string section in there debugging/learning purposes

<?php //get contents of cron tab $output = shell_exec('crontab -l'); echo "<pre>$output</pre>";  //find string $cronjob = ('* * * * * /usr/local/bin/php /home/dldl1330/public_html/new/mailchimp.php'); if (strstr($output, $cronjob)) {    echo 'found'; } else {    echo 'not found'; }  //copy cron tab , remove string $newcron = str_replace($cronjob,"",$output); echo "<pre>$newcron</pre>";  file_put_contents('/tmp/crontab.txt', $newcron.php_eol); echo exec('crontab /tmp/crontab.txt');  ?>