Advanced Git Techniques

Git Help

List available subcommands and some concept guides. See 'git help ' or 'git help ' to read about a specific subcommand or concept.

# show helpful guides that come with Git
git help -g

# show helpful commands that come with Git
git help -a

TLDR

Simplified and community-driven man pages

brew install tldr
tldr git commit

Git-standup

Recall what you did on the last working day, or be nosy and find what someone else in your team did.

npm install -g git-standup
git-standup

---

Aliases and Functions

Aliases are helpers that let you define your own git calls. For example, you could set git a to run git add --all or you could configure git add -all to be gaa.

(1) .gitconfig

To add an alias, either navigate to ~/.gitconfig and fill it out in the following format:

[alias]
  co = checkout
  cm = commit
  p = push
  # Show verbose output about tags, branches or remotes
  tags = tag -l
  branches = branch -a
  remotes = remote -v

...or type in the command-line:

git config --global alias.cm commit

For an alias with multiple functions use quotes:

git config --global alias.ac 'add -A . && commit'

(2) .zshrc or .bash_profile

If you want even shorter aliases, you can configure them in your preferred shell configuration file. For example if you are using zsh, open its rc file vim ~/.zshrc and add a new alias like so:

alias gds="git diff --staged"

You can also add functions:

# clone repository and directly cd into it
gclone() {
  git clone "$1" && cd "$(basename "$1")"
}

Have a look at this example .zshrc configuration. Alternatively, you can also install oh-my-zsh to get a pre-configured list of many aliases.

---

Git Techniques

Speed Up Daily Tasks

What did I just commit?

Let's say that you just blindly committed changes with git commit -a and you're not sure what the actual content of the commit you just made was. You can show the latest commit on your current HEAD with:

git show

# or
git log -p -1

Switching Between Branches

To move to the previous branch in Git:

$ git checkout -
# Switched to branch 'master'

$ git checkout -
# Switched to branch 'next'

$ git checkout -
# Switched to branch 'master'

Alternatives:

git checkout @{-1}

# or create a shortcut
gco -

Styled Git Status

Show the index (changed files).

git status

# or simplify the output
git status -sb

Read more about the Git status command.

Styled Git Log

Running:

git log --graph --pretty='%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --all

# or use an alias
glola

Group commits by authors and title

git shortlog

Read more about the Git log command.

Git Query

A Git query allows you to search all your previous commit messages and find the most recent one matching the query.

$ git show :/query

where query (case-sensitive) is the term you want to search, this then finds the last one and gives details on the lines that were changed.

$ git show :/typo

Git Diff

Show changes between commits, commit and working tree, etc

# List all the conflicted files
git diff --name-only --diff-filter=U

# Unstaged changes since last commit
git diff

# Show both staged and unstaged changes
git diff HEAD

# Changes staged for commit
git diff --cached
git diff --staged

# or just use an alias
gds

What changed since two weeks?

git log --no-merges --raw --since='2 weeks ago'

# or use this alternative
git whatchanged --since='2 weeks ago'

Prunes references to remote branches that have been deleted in the remote.

git fetch -p

# or use this alternative
git remote prune origin

# or just an alias
grpo

Patching & Interactive Staging

I want to stage part of a new file, but not the whole file. Normally, if you want to stage part of a file, you run this:

$ git add --patch filename.x

-p will work for short. This will open interactive mode. You would be able to use the s option to split the commit - however, if the file is new, you will not have this option. To add a new file, do this:

$ git add -N filename.x

Then, you will need to use the e option to manually choose which lines to add. Running git diff --cached will show you which lines you have staged compared to which are still saved locally.

I want to add changes in one file to two different commits

git add will add the entire file to a commit. git add -p will allow to interactively select which changes you want to add.

Stage parts of a changed file, instead of the entire file

git add -p

y  stage this hunk
n  do not stage this hunk
a  stage this and all the remaining hunks in the file
d  do not stage this hunk nor any of the remaining hunks in the file
j  leave this hunk undecided, see next undecided hunk
J  leave this hunk undecided, see next hunk
k  leave this hunk undecided, see previous undecided hunk
K  leave this hunk undecided, see previous hunk
s  split the current hunk into smaller hunks

Interactiv staging

git add -i

--interactive (or -i) is the big brother of --patch. --patch only lets you decide about the individual hunks in files. --interactive enters the interactive mode, and is a bit more powerful. So powerful that it has its own little submenu:

Patching Checkouts and Stashes

Checkout undesired changes, keep good changes.

$ git checkout -p
# Answer y to all of the snippets you want to drop

Another strategy involves using stash. Stash all the good changes, reset working copy, and reapply good changes.

$ git stash -p
# Select all of the snippets you want to save
$ git reset --hard
$ git stash pop

Rewriting History

(1) Amending Commits

# Reword the previous commit message
git commit -v --amend

# Amend author
git commit --amend --author='Author Name <[email protected]>'

# Reset author, after author has been changed in the global config.
git commit --amend --reset-author --no-edit

(2) Rebasing Feature Branches

! The golden rule of git rebase is to never use it on public branches.

# Change previous two commits with an interactive rebase.
git rebase --interactive HEAD~2

# Forced push but still ensure you don't overwrite other's work
git push --force-with-lease <remote-name> <branch-name>

Git Reflog

If you accidentally do git reset --hard, you can normally still get your commit back, as git keeps a log of everything for a few days.

git reflog

You'll see a list of your past commits, and a commit for the reset. Choose the SHA of the commit you want to return to, and reset again:

git reset --hard SHA1234

And you should be good to go.