Re: [PATCH 2/4] .gitignore: remove dangling file

From: Felipe Contreras <felipe.contreras@gmail.com>
Date: Dec 2, 2020, 03:30 UTC
Message-ID: <CAMP44s2kHshVBRaQ=+jMTLvvxo+aQyB_XP8Et=+ZZt8XhpDufQ@mail.gmail.com>
In-Reply-To: <X8b7UMcsfaD0OFv4@coredump.intra.peff.net>

On Tue, Dec 1, 2020 at 8:26 PM Jeff King <peff@peff.net> wrote:

Show 15 quoted lines

> I was curious how hard it would be to find unused ones, and it is not
> too bad:
>
>   find * -type f |
>   git check-ignore --stdin -v |
>   perl -e '
>     my $ignore_file = shift;
>     while (<>) {
>       /^\Q$ignore_file\E:(\d+)/ and $seen{$1} = 1;
>     }
>     open(my $fh, "<", $ignore_file);
>     while (<$fh>) {
>       print "$. $_" unless $seen{$.};
>     }
>   ' .gitignore

Or to use a more modern language:

find * -type f |
  git check-ignore --stdin -v |
  ruby -e '
    $ignore_file = ARGV.first
    $seen = {}
    $stdin.each do |e|
      e =~ /^#{Regexp.quote($ignore_file)}:(\d+)/ and $seen[$1.to_i - 1] = true
    end
    ARGF.each_with_index do |e, i|
      print "#{i} #{e}" unless $seen[i]
    end
  ' .gitignore

-- 
Felipe Contreras