Git command-line

Git is a free, open-source distributed version control system that helps us organize and manage projects easily and efficiently.

It is by far the most widely used SCM tool for handling small and large projects alike. Because Git has so many capabilities, it can be easy to overlook or forget some of its handiest everyday features.

Here is a practical guide to commands and configurations that are especially useful to keep in your toolkit.

Cloning into a specific folder

By default, Git creates a folder named after the remote repository:

BASH

git clone <remote-url>/repository.git

If you want the local folder to have a different name, pass the target folder name as the final argument:

BASH

git clone <remote-url>/repository.git my-custom-folder

In that case, the repository will be placed inside a folder named my-custom-folder.

Using different GitHub accounts (SSH keys)

When balancing client, work, and personal projects, you often need to use separate GitHub accounts without re-authenticating on every push.

SSH host aliases make this seamless. When you generate an SSH key (for example, with ed25519), your default ~/.ssh/config file usually looks like this:

TEXT

Host github.com
  User git
  IdentityFile ~/.ssh/id_ed25519

To configure a second account, add an alias block pointing to the secondary SSH key:

TEXT

# Default personal account
Host github.com
  User git
  IdentityFile ~/.ssh/id_ed25519

# Secondary / work account
Host secondary-github.com
  HostName github.com
  User git
  IdentityFile ~/.ssh/secondary_account_id_ed25519

With HostName github.com, Git routes the connection to github.com while using the secondary_account_id_ed25519 key whenever the hostname secondary-github.com is used in a remote URL:

BASH

# Uses default SSH key:
git clone git@github.com:rafaeltonholo/portfolio.git

# Uses secondary SSH key:
git clone git@secondary-github.com:rafaeltonholo/portfolio.git

This trick also works for GitLab, Bitbucket, and self-hosted instances.

Cleaning up branches deleted on remote

When pull requests merge and remote branches are deleted, your local repository retains references to them. You can prune deleted remote-tracking branches and remove the matching local branches in one command:

BASH

git fetch -p
git branch -vv | \
    grep ': gone' | \
    grep -v "^\*" | \
    grep -v "^\+" | \
    grep -v "^- " | \
    awk '/: gone]/{print $1}' | \
    xargs git branch -D

How this works:

git fetch -p: Prunes remote-tracking references that no longer exist on the remote.
git branch -vv: Lists local branches with tracking details; deleted tracking branches are flagged with : gone.
grep ': gone': Filters down to branches whose upstreams are gone.
grep -v "^\*": Excludes the currently checked-out branch.
grep -v "^\+" and grep -v "^- ": Trims worktree indicator lines.
awk '/: gone]/{print $1}': Extracts only the branch name.
xargs git branch -D: Deletes each pruned branch locally.

Prettier, more concise git logs

Running plain git log can be overwhelming when you just want a quick overview of recent history:

BASH

$ git log

commit 4bb2b59ec0ac4ed853c586ba29f0c0a5d94598da (HEAD -> main, origin/main)
Author: Rafael Tonholo <rafael@tonholo.dev>
Date:   Thu Oct 3 18:20:41 2024 -0300

    ci: deploy resume changes

Git provides several flags to format logs more cleanly:

BASH

git log --graph --oneline --decorate --all

Useful flags to combine:

--oneline: Condenses each commit to its abbreviated hash and title line.
--graph: Draws an ASCII branch and merge tree.
--decorate: Shows branch and tag pointers.
--stat: Adds diffstat summaries per commit.
--author="Name": Filters commits by author.

You can alias this in ~/.gitconfig for quick access:

INI

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

Upcoming topics to explore

Stay tuned for upcoming deep-dives covering:

Amending commits cleanly without duplicate history
Interactive rebasing and squash strategies
When to merge vs. when to rebase
Git submodules: setup, removal, pros, and cons
Trunk-based development vs. Git-flow in production teams