Not a problem. here is the code:

foreach $file (@infile){
    open(IN, '<', "$file") or warn $! and next;
    open(OUT, '>', $outpath.basename($file))
    or warn $! and next;
            while (<IN>) {
            substr($_,279) =~ s/$regex/$substitute{$1}/g;
            print OUT $_;
            }
                
}
[download]

These lines are very long. much longer than 279... I'm really confused.