opendir ( my $dir, "/mnt/data/Programming")
   or die "Can't open directory: $!\n";
my @files = readdir( $dir );
closedir( $dir );

##</code><code>##

foreach my $file ( grep { -f "$path/$_" } @files )
{
    open( my $fh, '<', "$path/$file" )
       or die "Unable to open '$file': $!\n";

    while( <$fh> )
    {
        # process each line here.
    }
}