Git tips and tricks

Git comes with a ton of commands, and that's probably an understatement.

The internet is full of Git tips and it's hard if not impossible to know

them all, but sometimes you stumble upon an aha! moment that changes your

whole workflow.

In this post, we gathered some Git tips and tricks we use at GitLab everyday.

Hopefully they will add up to your aha! moment.

• TOC

Intro

Almost everybody at GitLab will need to use Git at some point. For newcomers

who know nothing about Git that can be a fearsome experience. We have a

Git cheatsheet and a #git-help chat channel where we ask questions and

provide help if some of us get stuck. That's a quick way to provide help, and

if something is complicated or someone has messed up their local repository and

needs immediate help, there's always a person to jump on a quick call.

Here's a pack of Git tricks that will leverage your Git-fu and you'll hopefully

find useful. Remember, the list is far from exhaustive :)

Git's built-in help

The majority of users rely on sites like StackOverflow to find answers to their

Git problems, but how often do you use Git's built-in help to find more about a

command you are struggling with?

The most common commands

Run git help to print a list of the most common commands. You'll probably

notice you've used most of them, but how well do you really know them?

Thankfully, there is a help page for every command!

A help page for every command

Git's documentation is comprehensive and is automatically installed with Git.

Run git help <command> to find out all about a command's behavior and what

options it can take.

Git guides

Git comes with a handful of guides ready for you to explore. Run git help -g

to see what's available:

The common Git guides are:

   attributes   Defining attributes per path
   everyday     Everyday Git With 20 Commands Or So
   glossary     A Git glossary
   ignore       Specifies intentionally untracked files to ignore
   modules      Defining submodule properties
   revisions    Specifying revisions and ranges for Git
   tutorial     A tutorial introduction to Git (for version 1.5.1 or newer)
   workflows    An overview of recommended workflows with Git

Jump to a Git tutorial with git help tutorial, go through the glossary with

git help glossary or learn about the most common commands with

git help everyday.

See the repository status in your terminal's prompt

It's very useful to be able to visualize the status of your repository at any

given time. While there are 3rd party tools that include this information

(oh-my-zsh anyone?), Git itself provides a script named git-prompt.sh

that does exactly that. You can download it and follow the

instructions in it to install and use it in your system. If you're using Linux

and have installed Git with your package manager, it may already be

present on your system, usually under /etc/bash_completion.d/.

Go ahead and replace your boring shell prompt with something like this:

{: .shadow}

Taken from oh-my-zsh's themes wiki

Autocompletion for Git commands

You may also find it useful to use the completion scripts that provide Git

command completion for bash, tcsh and zsh. Again, follow the instructions

inside the scripts to learn how to install them. Once done, you can try out

typing a command.

Let's say you want to type git pull. If Git completion is enabled, typing

just the first letter with git p followed by Tab will show the

following:

pack-objects   -- create packed archive of objects

pack-redundant -- find redundant pack files

pack-refs      -- pack heads and tags for efficient repository access

parse-remote   -- routines to help parsing remote repository access
parameters

patch-id       -- compute unique ID for a patch

prune          -- prune all unreachable objects from the object database

prune-packed   -- remove extra objects that are already in pack files

pull           -- fetch from and merge with another repository or local
branch

push           -- update remote refs along with associated objects

To show all available commands, type git in your terminal followed by

Tab+ Tab, and see the magic happening.

Git plugins

Since Git is free software, it's easy for people to write scripts that extend

its functionality. Let's see some of the most common ones.

The git-extras plugin

If you want to enhance Git with more commands, you'll want to try out the

git-extras plugin. It includes commands like git info (show

information about the repository), git effort (number of commits per file),

and the list goes on. After you install it, make sure to visit

the documentation on the provided commands in order to understand

what each one does before using it.

The git-open plugin

If you want to quickly visit the website on which the repository you're on is

hosted, git-open is for you. All major providers are supported (GitLab, GitHub,

Bitbucket) and you can even use them all at the same time if you set

them as different remotes.

Install it, and try it out by cloning a repository from

GitLab.com. From your terminal navigate to that

repository and run git open to be transferred to the project's page on

GitLab.com.

It works by default for projects hosted on GitLab.com, but you can also use it

with your own GitLab instances. In that case, make sure to set up the domain

name with:

git config gitopen.gitlab.domain git.example.com

You can even open different remotes and branches if they have been set up.

Read more in the examples section.

.gitconfig on steroids

The .gitconfig file contains information on how you want Git to behave on

certain circumstances. There are options you can set at a repository level,

but you can also set them in a global .gitconfig so that all local config

will inherit its values. This file usually resides in your home directory.

If not, either you'll have to create it manually or it will be automatically

be created when you issue a command starting with git config --global as

we'll see below.

The very first encounter with .gitconfig was probably when you set your

name and email address for Git to know who you are.

To know more about the options .gitconfig can take, see the [Git documentation

on .gitconfig]gitconfig.

If you are using macOS or Linux, .gitconfig will probably be hidden if you are

trying to open it from a file manager. Either make sure the hidden files are

shown or open it using a command in the terminal: atom ~/.gitconfig.

Let's explore some of the most useful config options.

Set a global .gitignore

If you want to avoid committing files like .DS_Store, Vim swp files, etc.,

you can set up a global .gitignore file.

First create the file:

touch ~/.gitignore

Then run:

git config --global core.excludesFile ~/.gitignore

Or manually add the following to your ~/.gitconfig:

[core]
  excludesFile = ~/.gitignore

Gradually build up your own useful list of things you want Git to ignore. Read

the gitignore documentation to find out

more.

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Git docs source

Delete local branches that have been removed from remote on fetch/pull

You might already have a bunch of stale branches in your local repository that

no longer exist in the remote one. To delete them in each fetch/pull, run:

git config --global fetch.prune true

Or manually add the following to your ~/.gitconfig:

[fetch]
  prune = true

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Git docs source

Enable Git's autosquash feature by default

Autosquash makes it quicker and easier to squash or fixup commits during an

interactive rebase. It can be enabled for each rebase using

git rebase -i --autosquash, but it's easier to turn it on by default.

git config --global rebase.autosquash true

Or manually add the following to your ~/.gitconfig:

[rebase]
  autosquash = true

At this point, let us remind you of the perils of rebasing.

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Git docs source

(tip taken from thoughbot)

Extra info when using Git submodules

If you are using submodules, it might be useful to turn on the submodule summary.

From your terminal run:

git config --global status.submoduleSummary true

Or manually add the following to your ~/.gitconfig:

[status]
  submoduleSummary = true

---

Git docs source

Change the editor of Git's messages

You can change the default text editor for use by Git commands.

From git help var:

the order of preference is the $GIT_EDITOR environment variable, then

core.editor configuration, then $VISUAL, then $EDITOR, and then the

default chosen at compile time, which is usually vi.

Running git config --show-origin core.editor will tell you if core.editor

is set and from which file. This needs at least Git 2.8.

To change it to your favor editor (vim, emacs, atom, etc.), run:

git config --global core.editor vim

Or manually add the following to your ~/.gitconfig:

[core]
  editor = vim

---

Git docs source

Change the tool with which diffs are shown

git diff is useful as it shows the changes that are not currently staged.

When running this command Git usually uses its internal tool and displays

the changes in your terminal.

If you don't like the default difftool there are a couple of others to choose

from:

• vimdiff - Vim's built-in vimdiff

• magit - Emacs most popular tool is Magit

• meld - A visual diff and merge tool written in Python

• kdiff3 - A diff and merge program written in Qt

To change the default tool for watching diffs run the following:

git config --global diff.tool vimdiff

Or manually add the following to your ~/.gitconfig:

[diff]
  tool = vimdiff

Also related is the merge.tool setting which can be set to a tool to be used

as the merge resolution program. Similarly:

git config --global merge.tool vimdiff

Or manually add the following to your ~/.gitconfig:

[merge]
  tool = vimdiff

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Git docs source

Aliases

Git commands can take a lot of flags at a time. For example, for a log graph

you can use the following command:

git log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s
%Cgreen(%cr)%Creset' --abbrev-commit --date=relative

You sure don't want to type this every time you need to run it. For that purpose,

Git supports aliases, which are custom user-defined commands that build on top

of the core ones. They are defined in ~/.gitconfig under the [alias] group.

Open ~/.gitconfig with your editor and start adding stuff.

Add an alias to pretty log graphs

In your ~/.gitconfig add:

[alias]
  lg = log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr)%Creset' --abbrev-commit --date=relative
  lol = log --graph --decorate --pretty=oneline --abbrev-commit

Next time you want the pretty log to appear, run: git lg or git lol for

some pretty log graphs.

Add an alias to checkout merge requests locally

A merge request contains all the history from a repository, plus the additional

commits added to the branch associated with the merge request. Note that you

can checkout a public merge request locally even if the source project is a fork

(even a private fork) of the target project.

To checkout a merge request locally, add the following alias to your ~/.gitconfig:

[alias]
  mr = !sh -c 'git fetch $1 merge-requests/$2/head:mr-$1-$2 && git checkout mr-$1-$2' -

Now you can check out a particular merge request from any repository and any

remote. For example, to check out the merge request with ID 5 as shown in GitLab

from the upstream remote, run:

git mr upstream 5

This will fetch the merge request into a local mr-upstream-5 branch and check

it out. In the above example, upstream is the remote that points to GitLab

which you can find out by running git remote -v.

The Oh-my-zsh Git aliases plugin

If you are an Oh My Zsh user you'll probably know this already.

Learn how you can enable the Git plugin provided with Oh My Zsh and

start using the short commands to save time. Some examples are:

• gl instead of git pull

• gp instead of git push

• gco instead of git checkout

Git command line tips

Here's a list of Git tips we gathered.

An alias of HEAD

Did you know @ is the same as HEAD? Using it during a rebase is a life saver:

git rebase -i @~2

Quickly checkout the previous branch you were on

A dash (-) refers to the branch you were on before the current one.

Use it to checkout the previous branch (source):

# Checkout master

git checkout master


# Create and checkout to a new branch

git checkout -b git-tips


# Checkout master

git checkout master


# Checkout to the previous branch (git-tips)

git checkout -

Delete local branches which have already been merged into master

If you are working everyday on a project that gets contributions all the time,

the local branches number increases without noticing it. Run the following

command to delete all local branches that are already merged into master

(source):

# Make sure you have checked out master first

git checkout master


# Delete merged branches to master except master

git branch --merged master | grep -v "master" | xargs -n 1 git branch -d

In the event that you accidentally delete master (💩 happens), get it back with:

git checkout -b master origin/master

Delete local branches that no longer exist in the remote repo

To remove all tracking branches that you have locally but are no more present in

the remote repository (origin):

git remote prune origin

Use the --dry-run flag to only see what branches will be pruned, but not

actually prune them:

git remote prune origin --dry-run

If you want this to be run automatically every time you fetch/pull, see

how to add it to your .gitconfig.

Checking out a new branch from a base branch

You can checkout a new branch from a base branch without first checking out

the base branch. Confusing? Here's an example.

If you are on a branch named old-branch and you want to

checkout new-branch based off master, you'd normally do:

git checkout master

git checkout -b new-branch

There's a quicker way though. While still on the old-branch, run:

git checkout -b new-branch master

The pattern is the following:

git checkout -b new_branch base_branch

References

• Thoughbot's gitconfig file contains useful tips some of which are also present in this post

• A collection of Git tips

• Git and Vimdiff

• Git's official site

Conclusion

As always, writing something about Git, only scratches the surface. While some

of the tips included in this post might come in handy, there are sure a lot

of other stuff we're not familiar with.

{: .shadow}

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Image: "Branching illustration" by Jason Long is licensed under CC BY 3.0