#!/usr/bin/perl

# http://perlmonks.org/?node_id=1120387

use strict;
use warnings;


my $log_dir   = '/home/user1';
my $log_file  = "$log_dir/trans.log";

my $trans_dir = '/data/directoy1';


# Log handles
if ( not open my $loghandle, ">>", $log_file ) {        # lexical handle and three argument form of open()
    # syslog ... # what's this?
    die "Cannot open file $log_file: $!";
}



# maybe instead of opendir ... and readdir ...
my @files = grep { -f } glob( "$trans_dir/*OT*" );


foreach my $file (@files) {

   print STDERR "File: $file\n";
   print "$file\n";

   open my $fh, "<", $file                              # same here; lexical file handle and 3-arg-form of open()
       or die "Cannot open $file: $!";

   while ( my $line = <$fh> ) {

        if ( (my $participant) = $line =~ m{(.....)/} ) {       # explicitely use $line for regex
            print "$participant";                               # only print when match was found
        }
   }

   close $fh;
}