Re: forking and monitoring processes

[zentara]

Hi, here is a script that will work for you. I use the @ARGV trick to loop thru each line in a directory full of files, and do a regex, then cancel all forks if a regex matches. You don't need to worry about different filehandles, doing it this way. (This works very fast, so you may get 2 matches by the time the forks can be shut down, but that shouldn't be a problem.

#!/usr/bin/perl
use warnings;
use strict;
use Parallel::ForkManager;

my $dir = shift || '.';
my @dirs =  get_sub_dirs($dir);

my $max_tasks   = 3;
my $pm = new Parallel::ForkManager($max_tasks);
$|++;
my $start = time();

for my $dir (@dirs) {
    my $pid = $pm->start and next;
    printf "Begin processing $dir at %d secs.....\n", time() - $start;

    #push all the $dir/files into @ARGV and search through them  
    #line by line 

    @ARGV = <$dir/*>;

     while (<ARGV>) {
        close ARGV if eof;
         if( $_ =~ /desktop/){
           print "$ARGV: $. :$_\n";
           $pm->finish;
           goto END;
        }
     }
    END:
    printf ".... $dir done at %d secs!\n", time() - $start;
    $pm->finish;
}

print " all done\n";
exit;

########################################################## 
sub get_sub_dirs {
 my $dir = shift;
 opendir my $dh, $dir or die "Error: $!";

 my @dirs = grep { -d $_ } readdir $dh;
 @dirs = grep !/^\.\.?$/, @dirs;
 closedir $dh;
 return @dirs;
}

[Anonymous Monk]

Hello,

Could you please tell me what @ARGV = <$dir/*> does?

I actually want to execute a command ... shd I use backticks instead to capture the output?

so @output = `Start_Process.exe param1 param2`;

Then parse through each line of @output to see if I find the error messages I am looking for and then close out all the other forks immediately using close ARGV?

Thanks.

[zentara]

It "globs" all the files in $dir into @ARGV, which is a special array for input. It's advantage over a regular array is that you can go thru it "line-by-line" without having to open and close each file, which you would have to do with a regular array of files. Your @output plan sounds about right, but there are usually a few glitches to work out, so test,test,test. :-)