Redirecting standard error in perl script to /dev/null

gaurav_s · 01-09-2015, 02:13 AM

In a perl script i am executing below command.
whenever $pName is empty it ,program is printing some error message . I don't want to print those error message ,so i am using >/dev/null 2>&1 as below. But, still i am getting error message.

my $procID=`ps -ef | grep $pName | grep -v grep |awk '{print \$2}' | head -1 >/dev/null 2>&1 ` ;

Please suggest better way to achieve this.

pan64 · 01-09-2015, 02:27 AM

yes. that redirection will redirect the output of head, not the grep inside.
I can only suggest you to drop that line and implement it in perl (as you use perl already)

Code:

open (PS, "ps -ef") or die;
while ( <PS> )
{
    # evaluate things here
}
close PS;

Another tip is to avoid finding procID if pName is empty (do not execute that line at all).

gaurav_s · 01-12-2015, 03:15 AM

Thanks a lot