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Git

Basic actions

Clone a remote repo:

git clone $REMOTE_REPO_URL

Get the status of your repo:

git status

Get the status of your repo listing all the files:

git status -u

Stage a change:

git add $FILE_PATH

Choose chunks of code you want to stage:

git add -p $FILE_PATH

Commit a change and sign it:

git commit -s -m "$COMMIT_MESSAGE"

Add new changes to the last commit:

git commit --amend

Push your change to a remote repo:

git push -u origin $BRANCH_NAME

Create a branch:

git checkout -b $BRANCH_NAME

Search some code in the git history:

git rev-list --all | xargs git grep -F ‘$STRING_TO_SEARCH’

Standardise commit messages

Using Commitizen to have a common format.

Install commitizen globally:

npm install -g commitizen

Install the commitizen adapter globally:

npm install -g cz-conventional-changelog

Create a .czrc file in the home directory, with the path referring to the preferred, globally-installed, commitizen adapter:

echo "{ \"path\": \"$(npm root -g)/cz-conventional-changelog\" }" > ~/.czrc

Now, use git czto handle the commit.

Here is are the type of changes that you can commit:

  • feat: A new feature
  • fix: A bug fix
  • docs: Documentation only changes
  • style: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
  • refactor: A code change that neither fixes a bug nor adds a feature
  • perf: A code change that improves performance
  • test: Adding missing or correcting existing tests
  • chore: Changes to the build process or auxiliary tools and libraries such as documentation generation

Check differences

Check all changes since last commit:

git diff --color-words

Check changes since last commit for a specific file:

git diff --color-words HEAD $PATH_TO_FILE

Check changes between two commits:

git diff --color-words $COMMIT_NUMBER $COMMIT_NUMBER

Check changes between two commits for a specific file:

git diff --color-words $COMMIT_NUMBER $COMMIT_NUMBER $PATH_TO_FILE

Check changes between two branches:

git diff --color-words $BRANCH_NAME $BRANCH_NAME

Check changes between two branches for a specific file:

git diff --color-words $BRANCH_NAME $BRANCH_NAME $PATH_TO_FILE

Check stages changes:

git diff --staged

Commit history managment

Check commit history:

git log --oneline --graph --color

Better git log:

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

Check commit history with changes:

git log -p

Add file change to the last commit:

git commit --am -s -m "$COMMIT_MESSAGE"

Count the number of commits on a specific branch:

git rev-list --count $BRANCH_NAME

Branch managment

Delete local branch:

git branch -d $BRANCH_NAME

Delete remote branch:

git push origin --delete $BRANCH_NAME

Pulls the changes from the remote branch to the local branch and makes a merge:

git pull origin $BRANCH_NAME

Rebase a base branch in current branch:

git rebase $BASE_BRANCH

Rebase a remote branch in current branch:

git pull --rebase origin master

Rebase a remote branch in current branch and stash changes:

git pull --rebase --autostash origin master

Rename a branch:

git branch -m $BRANCH_OLD_NAME $BRANCH_NEW_NAME
git push origin :$BRANCH_OLD_NAME $BRANCH_NEW_NAME
git push origin -u $BRANCH_NEW_NAME

Copy a file from a branch to the current one:

git checkout $BRANCH_TO_COPY_FROM $PATH_OF_THE_FILE_TO_COPY

Delete local branch that has been deleted remotely:

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

Delete local branch that are not master:

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

Start a new git repository

git init
git add .
git commit -m "First commit"
git remote add origin $REPO_URL
git push -u origin master

Config managment

To set the default config to be used, used git config --global --edit:

[color]
     ui = true
[alias]
     lop = log --pretty=format:"%C(yellow)%h\\ %Cred%ad\\ %Cblue%an%Cgreen%d\\ %Creset%s" --date=short
     ll = log --pretty=format:"%C(yellow)%h%Cred%d\\ %Creset%s%Cblue\\ [%cn]" --decorate --numstat

Check current config:

git config -l

Set username for the repo:

git config user.name "$NAME"

Set username globally:

git config --global user.name "$NAME"

Set email for the repo:

git config user.email "$EMAIL"

Set email globally:

git config --global user.email "$EMAIL"

Set a GPG key to be used to sing commits:

gpg --list-secret-keys --keyid-format LONG
# Copy the GPG key ID that starts with sec
git config user.signingkey 30F2B65B9246B6CA
# Automatically sign commits
git config commit.gpgsign true

Set GPG program to use (usefull to solve gpg: signing failed: secret key not available):

git config --global gpg.program gpg2

Enable credential helper to not have to retype your password each time you want to do something:

git config credential.helper store

Submodules

Clone repo with submodules (5 submodules at once):

git clone --recursive --jobs 5 $GIT_SUBMODULE_REPO_URL

Pull all the submodules updates:

git pull --recurse-submodules

Create a submodule:

git submodule add -b master --name $SUBMODULE_NAME $GIT_SUBMODULE_REPO_URL $SUBMODULE_PATH

Delete a submodule:

# Delete the relevant section from the .gitmodules file
git add .gitmodules
git submodule deinit $PATH_TO_SUBMODULE
git rm $PATH_TO_SUBMODULE
git commit -m "Removed submodule"
rm -rf .git/modules/$PATH_TO_SUBMODULE

Tips and tricks

I committed and immediately realized I need to make one small change:

# make your change
git add . # or add individual files
git commit --amend --no-edit

I accidentally committed something to master that should have been on a new branch:

# create a new branch from the current state of master
git branch $SOME_NEW_BRANCH
# remove the last commit from the master branch
git reset HEAD~ --hard
git checkout $SOME_NEW_BRANCH
# your commit lives in this branch now

I accidentally committed to the wrong branch:

# undo the last commit, but leave the changes available
git reset HEAD~ --soft
git stash
# move to the correct branch
git checkout $NAME_OF_THE_CORRECT_BRANCH
git stash pop
git add . # or add individual files
git commit -m "your message here";
# now your changes are on the correct branch

I need to undo the last commit:

git revert --no-edit HEAD
# git will create a new commit that undoes the last commit

I need to undo a commit from like 5 commits ago:

# find the commit you need to undo
git log
# use the arrow keys to scroll up and down in history
# once you've found your commit, save the hash
git revert --edit [saved hash]
# git will create a new commit that undoes that commit with the message you will have specified

I need to undo a commit from like 5 commits ago:

# find the commit you need to undo
git log
# use the arrow keys to scroll up and down in history
# once you've found your commit, save the hash
git revert --no-edit [saved hash]
# git will create a new commit that undoes that commit

I need to undo a commit from like 5 commit ago, and I want to review the changes made by the revert statement before committing them:

# find the commit you need to undo
git log
# use the arrow keys to scroll up and down in history
# once you've found your commit, save the hash
git revert --no-commit [saved hash]
# git will not create a new commit that undoes that commit

I need to undo my changes to a file:

# find a hash for a commit before the file was changed
git log
# use the arrow keys to scroll up and down in history
# once you've found your commit, save the hash
git checkout [saved hash] -- path/to/file
# the old version of the file will be in your index
git commit -m "Wow, you don't have to copy-paste to undo"

Thanks to Frumusanu Razvan for this tricks

Trigger the CI without making changes to the code base:

git commit --allow-empty -s -m "Trigger CI"