#!/usr/bin/perl

use strict;
use warnings;
use Tie::File;

my $file = 'filename.txt';

tie my @lines, 'Tie::File', $file or die $!;
for my $line ( @lines ){
    $line =~ s/^\s+|\s+$//;
    $line =~ s/\s+/ /g;
    $line =~ s/\(\s+\)/ /g;
}
untie @lines;