The following script processes all .csv file in the directory as one stream:

#!/usr/bin/perl

use strict;
use warnings;

my $logdir = 'c:/tmp/logs';
{
    opendir DIR, $logdir or die "error opening $logdir: $!\n";
    local @ARGV = map { $logdir . '/' . $_ } grep /\.csv$/, readdir DI
+R;
    closedir DIR or die "error closing $logdir: $!\n";

    while ( <> ) {
        #process the line
    }
}
[download]

HTH,
Paul