Learn how to add documentation to Git package in NixOS and customize the git help command for your aliases with this easy tutorial.
One of the features of Git is that you can create aliases for common commands, such as git status or git commit. However, if you want to get more information about your aliases, the default git help command may not be very helpful. It will only print the alias configuration value, which may not be very descriptive or informative.
In this article, we will show you how to add documentation to Git package in NixOS and customize the git help command for your aliases. This way, you can provide detailed help for your aliases, in the same way as git help diff and others do. We will use the NixOS operating system, which is a Linux distribution that uses the Nix package manager. Nix allows you to declaratively specify and manage your system configuration, packages, and dependencies.
Table of Contents
- How to Create Git Aliases in NixOS?
- How to Add Documentation to Git Package in NixOS?
- Frequently Asked Questions (FAQs)
- Question: What is NixOS and Nix?
- Question: How can I list all the Git aliases that I have defined?
- Question: How can I remove a Git alias that I no longer need?
- Question: How can I create more complex Git aliases that involve multiple commands or arguments?
- Summary
How to Create Git Aliases in NixOS?
Git aliases are shortcuts for common Git commands that you can define in your Git configuration file. For example, you can create an alias for git status as git st, or an alias for git log –graph –oneline –decorate –all as git lg. To create Git aliases in NixOS, you can use the config.programs.git module in your configuration.nix file. For example, you can add the following lines to your configuration.nix file:
{ config, pkgs, ... }:
{
# ...
programs.git = {
enable = true;
aliases = {
st = "status";
lg = "log --graph --oneline --decorate --all";
};
};
# ...
}
Then, you can apply the changes with the nixos-rebuild switch command. After that, you can use your aliases as normal Git commands, such as git st or git lg.
How to Add Documentation to Git Package in NixOS?
By default, the git help command will print the alias configuration value for your aliases, which may not be very informative. For example, if you run git help st, you will see something like this:
$ git help st
'st' is aliased to 'status'
However, you may want to provide more detailed help for your aliases, in the same way as git help diff and others do. For example, you may want to see something like this:
$ git help st
GIT-ST(1) Git Manual GIT-ST(1)
NAME
git-st - Show the working tree status
SYNOPSIS
git st [<options>...]
DESCRIPTION
Displays paths that have differences between the index file and the
current HEAD commit, paths that have differences between the working
tree and the index file, and paths in the working tree that are not
tracked by Git (and are not ignored by gitignore(5)). The first are
what you would commit by running git commit; the second and third are
what you could commit by running git add before running git commit.
OPTIONS
-s, --short
Give the output in the short-format.
-b, --branch
Show the branch and tracking info even in short-format.
--help
Show help message.
EXAMPLES
Show the working tree status in short format:
$ git st -s
M README
A file.c
?? file.h
Show the working tree status with branch information:
$ git st -b
## master...origin/master
M README
A file.c
?? file.h
GIT
Part of the git(1) suite
Git 2.33.1 10/18/2023 GIT-ST(1)
To achieve this, you need to add some documentation files to the Git package in NixOS. The documentation files should be in the same format as the existing Git manual pages, which are written in AsciiDoc. You can find the source files of the Git manual pages in the Git repository, under the Documentation directory.
To add documentation to Git package in NixOS, you can use the overrideAttrs function to modify the attributes of the Git package derivation. A derivation is a Nix expression that describes how to build a package, such as its dependencies, sources, patches, build commands, and outputs. The overrideAttrs function allows you to change some of the attributes of a derivation, such as the postInstall attribute, which specifies commands to run after the installation of the package.
For example, you can add the following lines to your configuration.nix file:
{ config, pkgs, ... }:
{
# ...
programs.git.package = pkgs.gitFull.overrideAttrs (old: {
postInstall = old.postInstall + ''
cp ${./includes/git-aliases/docs}/* $doc/share/doc/git/
'';
});
# ...
}
This will copy the documentation files from the ./includes/git-aliases/docs directory to the $doc/share/doc/git/ directory, where the Git manual pages are installed. The $doc variable refers to the output path of the doc output of the Git package derivation. The ./includes/git-aliases/docs directory should contain the documentation files for your aliases, such as git-st.txt or git-lg.txt. These files should be in the AsciiDoc format, and follow the same structure and style as the existing Git manual pages.
After adding the documentation files, you need to rebuild the Git package with the nixos-rebuild switch command. Then, you can use the git help command to see the documentation for your aliases, such as git help st or git help lg.
Frequently Asked Questions (FAQs)
Question: What is NixOS and Nix?
Answer: NixOS is a Linux distribution that is built on top of the Nix package manager. Nix is a powerful tool that allows you to declaratively specify and manage your system configuration, packages, and dependencies. Nix ensures that your system is always in a consistent state, and that you can easily roll back to previous versions if something goes wrong. Nix also supports multiple versions of the same package, and allows you to create isolated environments for different projects.
NixOS uses Nix to manage the entire system configuration, including the kernel, applications, services, and user settings. You can write your system configuration in a file called configuration.nix, and then apply it with the nixos-rebuild command. NixOS also supports modules, which are reusable pieces of configuration that can be imported and customized.
Question: How can I list all the Git aliases that I have defined?
Answer: You can use the git config –get-regexp ‘^alias\.’ command to list all the Git aliases that you have defined, along with their configuration values. Alternatively, you can use the git alias command, which is an alias for the same command.
Question: How can I remove a Git alias that I no longer need?
Answer: You can use the git config –unset alias.<name> command to remove a Git alias that you no longer need, where <name> is the name of the alias. For example, you can use git config –unset alias.st to remove the st alias. Alternatively, you can edit the ~/.gitconfig file and delete the corresponding line under the [alias] section.
Question: How can I create more complex Git aliases that involve multiple commands or arguments?
Answer: You can use the ! character to indicate that the alias should be executed by the shell, rather than by Git. This allows you to use shell features, such as pipes, variables, loops, or functions, in your aliases. For example, you can create an alias for git log –graph –oneline –decorate –all as git lg by using the following line in your ~/.gitconfig file:
[alias]
lg = !git log --graph --oneline --decorate --all
You can also use the sh -c command to execute a shell script as an alias. For example, you can create an alias for git add . && git commit -m <message> && git push as git acp <message> by using the following line in your ~/.gitconfig file:
[alias]
acp = !sh -c 'git add . && git commit -m "$1" && git push' -
The – at the end of the line indicates that the first argument of the alias should be passed to the shell script as $1.
Summary
In this article, we have learned how to add documentation to Git package in NixOS and customize the git help command for your aliases. We have seen how to use the NixOS operating system and the Nix package manager to declaratively specify and manage our system configuration, packages, and dependencies. We have also seen how to use the overrideAttrs function to modify the attributes of the Git package derivation, and how to write documentation files in the AsciiDoc format. We hope that this article has been helpful and informative for you, and that you have enjoyed learning how to customize Git help for your aliases in NixOS.