SSH keys let you authenticate with Git hosts without entering a password on every push or pull. This post covers generating keys for multiple providers, loading them into the SSH agent, and cloning repositories over SSH.

For general Git commands, see the Git cheatsheet.

Generate SSH keys

Generate a separate key for each provider (for example, GitHub and Bitbucket). Run ssh-keygen for each key, set a distinct filename, and optionally add a passphrase.

ssh-keygen -f ~/.ssh/id_rsa_github
ssh-keygen -f ~/.ssh/id_rsa_bitbucket

Add public keys to providers

Copy each public key (the .pub file) and add it to the provider:

• GitHub
• Bitbucket

cat ~/.ssh/id_rsa_github.pub
cat ~/.ssh/id_rsa_bitbucket.pub

Activate SSH keys

Start the SSH agent and add the keys you need for the current session.

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_rsa_github
ssh-add ~/.ssh/id_rsa_bitbucket

Verify the connection to a provider:

ssh -T git@github.com
ssh -T git@bitbucket.org

Shell aliases per provider

Add aliases to ~/.bashrc or ~/.zshrc to run the agent setup and load the correct key in one command.

alias ssh-github='eval "$(ssh-agent -s)" && ssh-add ~/.ssh/id_rsa_github'
alias ssh-bitbucket='eval "$(ssh-agent -s)" && ssh-add ~/.ssh/id_rsa_bitbucket'

Reload the shell configuration, then run the alias before working with that provider:

source ~/.zshrc
ssh-github

Clone repositories

Use the SSH remote URL when cloning. The host (github.com or bitbucket.org) determines which key the provider expects.

# git clone <REPOSITORY_URL>
git clone git@github.com:workspace/repo-name.git
git clone git@bitbucket.org:workspace/repo-name.git

If authentication fails, run the matching alias (for example, ssh-github) and try again.

Git is one of the version control systems, and it's a prerequisite for development jobs. This post covers most of the git commands I use.

Configuration

• Set user configuration for every project if you use multiple accounts

  git config user.name "<USERNAME>"
  git config user.email "<EMAIL_ADDRESS>"

• Use the current branch for push commands

  git config --global push.default current

• Set up SSH keys for GitHub, Bitbucket, and other providers - see Git SSH keys setup

Basic commands

• The repository setup
  • Initialize a git repository

    git init

  • Clone an existing repository

    # git clone <REPOSITORY_URL>
    git clone git@github.com:zsevic/pwa-starter.git

  • Add the remote repository

    # git remote add <REMOTE_NAME> <REPOSITORY_URL>
    git remote add origin git@github.com:zsevic/pwa-starter.git
    git remote add upstream git@github.com:zsevic/pwa-starter.git

  • Update the URL for the remote repository

    # git remote set-url <REMOTE_NAME> <REPOSITORY_URL>
    git remote set-url origin git@github.com:zsevic/pwa-starter.git

  • Get a list of configured remote connections

    git remote -v

• Branches
  • Get a list of the branches

    git branch

  • Create and switch to the new branch

    git checkout -b new-branch

  • Checkout to a specific commit and create a new branch out of it

    git log # find a hash from a specific commit
    git checkout <COMMIT_HASH>
    git switch -c <NEW_BRANCH_NAME>

  • Switch to another branch

    git checkout existing-branch

  • Rename the current branch

    git branch -m <NEW_BRANCH_NAME>

  • Delete branch

    git branch -D other-existing-branch

  • Fetch all the remote branches

    git fetch --all

  • Get a list of remote branches without cloning the repo or verify if the user has "read" access

    git ls-remote <REPOSITORY_URL>

• Get the status of the local changes

  git status

• Add new changes

  git add some-file.js
  git add .

• Commits
  • Commit the changes

    git commit -m "Commit message"

  • Empty commit without any files

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

  • Commit the changes and skip running git hooks

    git commit -m "Commit message" --no-verify

  • Update the latest commit message and add new changes to the latest commit

    git commit -m "Commit message" --amend

• Push the changes to the remote repository
  • Push the changes to the current branch when the current branch is configured as the default one

    git push

  • Push the changes to the remote branch

    # git push <REMOTE_NAME> <BRANCH_NAME>
    git push origin master

  • Force push the changes to the feature branch

    # git push <REMOTE_NAME> <FEATURE_BRANCH_NAME>
    git push origin feature-branch -f

• Fetch and merge remote changes to the local branch

  # git pull <REMOTE_NAME> <BRANCH_NAME>
  git pull origin master

• Remove (unstage) the changes from the local stage

  git reset some-file.js
  git reset

• Differences between commits
  • Get a difference compared to the latest commit

    git diff some-file.js
    git diff

  • Get a difference between the last two commits

    git diff HEAD^ HEAD
    # or
    git diff HEAD HEAD~1

• Revert the file changes

  git checkout -- some-file.js

• Merge the specified branch into the current one

  git merge <BRANCH_NAME>

• Revert specific commit. The following command creates a new commit

  git revert <COMMIT_HASH>

Miscellaneous

• Resets

  • Soft reset (commits are removed, but changes from the removed commits are staged)

    # git reset --soft HEAD~{NUMBER_OF_COMMITS_TO_SOFT_REMOVE}
    git reset --soft HEAD~2

  • Hard reset (both commits and changes are removed)

    # git reset --hard HEAD~{NUMBER_OF_COMMITS_TO_HARD_REMOVE}
    git reset --hard HEAD~1 # equal as git reset --hard HEAD^

  • Get the latest remote changes when pulling doesn't work

    git reset --hard origin/<BRANCH_NAME>

• Stashing

  git add .
  git stash save <STASH_NAME>
  git stash list
  git stash apply --index 0

• Tags

  • Remove the following tag locally

    git tag -d v0.13.29

• Find removed commits

  git reflog
  git checkout <COMMIT_HASH>

• Remove the initial commit

  git update-ref -d HEAD

• Patching

  • Create a patch from the latest commits

    # git format-patch -{NUMBER_OF_COMMITS}
    git format-patch -1

  • Apply the patches

    git apply 0001-latest-commit.patch

• Git submodules

  • Add git submodule

    # git submodule add -- <REPOSITORY_URL> <DIRECTORY_PATH>
    git submodule add -- git@github.com:zsevic/pwa-starter.git template

  • Retrieve the latest changes for the git submodule

    # git submodule update --remote <DIRECTORY_PATH>
    git submodule update --remote template

  • Resolve conflict in the submodule

    # git reset HEAD <DIRECTORY_PATH>
    git reset HEAD template
    git commit