Ignore Git

These are my notes on Git ignore.

I recently received a PR proposing some changes to a .gitignore file. One of the lines was formatted as follows:

/Crypt-OpenSSL-X509-*

Having used MANIFEST.SKIP etc. for Perl distributions, the line puzzled me, since I believed it to be resolving based on the file system root, but apparently the root relative to the .gitignore file.

From the Git documentation:

The pattern hello.* matches any file or directory whose name begins with hello.. If one wants to restrict this only to the directory and not in its subdirectories, one can prepend the pattern with a slash, i.e. /hello.*; the pattern now matches hello.txt, hello.c but not a/hello.java.

About Gitignore in General

When you create a new repository on GitHub you can specify a .gitignore based on the language of your choice. I have some older repositories where I have not added this and sometimes I set up no–GitHub repositories so they are created without a good initial .gitignore file.

All of the files used by GitHub are available in a repository, so you can easily fetch them from there.

If you are in the first scenario, you can use the gh extension: gh-gitignore, which will enumerate all of the available files using fzf.

If you are not using gh you could just use curl or similar

Example fetching .gitignore for Go:

curl -o gitignore https://raw.githubusercontent.com/github/gitignore/main/Go.gitignore

Ignoring

I had created a small utility gitignore located in my ~/bin/:

#!/usr/bin/env perl

use warnings;
use strict;

my $file = '.gitignore';

if (-e $file and -f _ and -w _) {
    open my $FOUT, '>>', $file or die "Unable to open file: $file - $!";
    print $FOUT "$ARGV[0]\n";
    close($FOUT);
} else {
    open my $FOUT, '>>', $file or die "Unable to open file: $file - $!";
    print $FOUT "$ARGV[0]\n";
    close($FOUT);
}

exit 0;

Where I would be able to ignore a file from the command line easily as:

gitignore file_to_be_ignored

Then I found out that git can already do this, via git-extras

git ignore file_to_be_ignored

You learn something every day.

Resources and References

Git documentation: gitignore
GitHub: gitignore - collection of gitignore examples
gh extension: gh-gitignore
GitHub: git-extras