If you use the /g modifier, you won't have infinite loops. 

while (my $line = <$infile>){
    if ($line =~ s/T/TT/g){
        # log $line and $. (line number)
    }
    print $new_file $line;
}
# overwrite old file with new file here

[download]

Perl 6 in German -- Difficult Sudoku

In reply to Re: Global substitution and report by moritz
in thread Global substitution and report by Outaspace

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