#!/usr/bin/env perl
use strict;
use warnings;

foreach my $file (grep { -f } @ARGV) {
    my $data = slurp_file ($file);
    my $new_data = join ('', (split /(SIL\n)/, $data, 5)[ 0 .. 3 ]);
    open my $OUT, '>', $file or die $!;
    print $OUT $new_data;
    close $OUT;
}

sub slurp_file { local (*ARGV, $/); @ARGV = shift; <> }