The above code works just fine. But I wonder there is any shorthand method to extract the same with a single line

Sure, its called a subroutine

 
print join ' ', win32perlProcPids(), "\n";

sub win32perlProcPids {
    my @tasks = `tasklist /FI "IMAGENAME eq perl.exe" /NH /FO CSV`;
    my @pids;
    foreach my $task (@tasks) {
        my @list = split /,/, $task;
        s/"//g for @list;
        push @pids, $list[1];
    }
    return @pids;
}
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