Putting "awk" inside of perl, system `cmd`

[polka4ever]

hello,

does perl allow/understand when i use AWK inside of a system command? I can't understand why this isn't working:

$pid=`ps -ef | grep java | egrep -v grep | awk '{print $2}'`;

print "$pid";

when i type: ps -ef | grep java | egrep -v grep | awk '{print $2}'

at the command prompt itself - i get ONLY the process ID.

But in perl - this returns the whole shebang - like the owner, process id, parent process id, etc, etc ...

I JUST want the process id (so i can kill it, in the next command).

~p0lka

 

[rharsh]

Didn't you post something very similar to this before? Did you not get the answer you were looking for?

If you're using perl, why bother with grep, egrep and awk? How about something like:

my @processes = `ps -ef`;
my @java = grep {$_ !~ /grep/} grep {/java/} @processes;
my @pids = map {(split)[1]} for @java;

foreach (@pids) {
    # Code to kill the process
}

Or, if you want to avoid using the temporary arrays, you could do:

my @pids = map {(split)[1]} grep {$_ !~ /grep/}
           grep {/java/} `ps -ef`;

It's been a while since I've used awk, but if I remember correctly, awk '{print $2}'` prints the second column, which in perl is array index 1. If this isn't correct, you'll need to change the field number associated with the split.

 

[polka4ever]

Thank you! Yes, I had posted something very similar & was still not able to do what I wanted, but this time I *believe* i've got it. I needed to "split", which I wasn't doing - so thank you for that hint.

system "rm seq2";
$ps=`ps -ef | grep java`;
print "$ps";
@pid=split /\s+/, "$ps";

print "@pid[1] \n";

system "kill @pid[1]";