my @files = qw(file1 file2 file3); # your log-files
    for (1..scalar(@files)){
      next unless(-e $files[$_-1]);
      my $pid=fork();
      if($pid==-1){
        warn($!);
        last;
      }
      if($pid){
        $pids{$pid}=1;
      }
      else{
        # do what you want with $files[$_-1]
        exit(0);
      }
    }
    while(keys %pids){
      my $pid=waitpid( -1, WNOHANG );
      die "$!" if $pid == -1;
      delete $pids{$pid};
    }
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