#!/usr/local/bin/perl -w

open FH,"+<file_name" or die "go away";

@x = <FH>;

$keep_bit=0;
foreach (@x) {
    if (/^RE$/) {
        $keep_bit++;
    }

    if ($keep_bit) {
        push(@y,$_);
    }
}
seek (FH,0,0);
print FH @y;
truncate(FH, tell(FH));
close FH;