How to get the current line number of a file open using Perl?

Question

open my $fp, \'<\', $file or die $!;

while (<$fp>) {
    my $line = $_;
    if ($line =~ /$regex/) {
        # How do I find out which line number this mat         


        

Answer 1

Don't use $., nor $_ or any global variable. Use this instead:

while(my $line = <FILE>) {
  print $line unless ${\*FILE}->input_line_number == 1;
}

To avoid this and a lot of others Perl gotchas you can use on Atom or VSCode packages like linter-perl. Stop making Perl a write-only language!

Answer 2

Use $. (see perldoc perlvar).

Answer 3

You can also do it through OO interface:

use IO::Handle;
# later on ...
my $n = $fp->input_line_number();

This is in perldoc perlvar, too.