in reply to which module - linux/process

you can use backticks, or a pipe open 
my $output = `ls -la`;
# or
open PIPE, "ls -la |";
while(<PIPE>)
{
    ....
}

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Oha

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Re^2: which module - linux/process
by salva (Canon) on Sep 25, 2007 at 10:55 UTC
    or system if the command output is not going to be used later: 
    system($command, @args);

    [download]

    It is documented in perlfunc

[reply]
[d/l]
[select]

      Yes, system(command,args) is what i use

      What i need is to wait for the above command to complete and control passed back to the perl script, so i can do something more in there

[reply]
[d/l]
        but that's what system does!

        Maybe the shell script you are calling is forking more processes and not waiting for them.

[reply]
[d/l]
        system will fork/exec and wait
[reply]
Re^2: which module - linux/process
by Anonymous Monk on Sep 25, 2007 at 10:55 UTC

    I was trying something on the lines of waitpid, fork and exec. But waitpid dint work for me

[reply]
      As noted, you will need to use the system(...) or `...` to execute any system-level commands. These commands will wait for the external processes to complete.

      But you mentioned you would like to try using fork and wait/waitpid, so try this example: 

          my $pid;
    if (defined($pid = fork)) {
        if ($pid) {
            &parent();
        } else {
            &child();
        }
    } else {
        die "Fork didn't work...\n";
    }

    sub child {
        print "Running child process instructions...\n";
        sleep 5;
    # If you have system-level commands to process,
    # you will still need to use system(...) or `...`
        exit;
    }

    sub parent {
        waitpid($pid,0); # Will wait for a specific child process
    #   wait;            # Will wait for ANY child process to finish
        print "Finished waiting for child process $pid\n";
    }

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[reply]
[d/l]
        exactly what i was looking for, thanks so much!
[reply]

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