Git

Git is a distributed revision control / software configuration management project created by Linus Torvalds, initially for the Linux kernel development.

Git is by far my favourite revision control system. I not only use it for software management, I also use it as my backup system for any of my text files.

Examples

Basic

• Quick help:

$ git help      # returns most common commands
$ git help -a   # get a list of all installed git commands
$ man git-add   # man page on the 'add' command

• Start a new git repository:

$ mkdir my_new_project && cd my_new_project
$ git init
# create some new files, then:
$ git add .
$ git commit
#~OR~
$ git commit -am 'initial commit message'

• See what has changed since last commit:

$ git diff

• A more concise way to view what has changed and what needs to be done:

$ git status

• Clone a specific remote branch:

$ git clone --single-branch --branch <branchname> <remote-repo>

Miscellaneous

• View current git user:

$ git config user.email

• Change to a different git user:

$ git config --global user.email "someone@somewhere.com"

• Check git log for a specific function in a specific (e.g., Python) file:

# Syntax:
$ git log -L :<funcname>:<file>

# Example:
$ git log -L :load_json:compare_rke_state_files.py
commit b5ac4b65f9554a32fbec64435171c07a20a52de8
Author: Christoph Champ <christoph.champ@gmail.com>
Date:   Sat Jun 15 18:47:12 2019 -0700
    initial commit of compare_rke_state_files.py
diff --git a/ansible/compare_rke_state_files.py b/ansible/compare_rke_state_files.py
--- /dev/null
+++ b/ansible/compare_rke_state_files.py
@@ -0,0 +8,6 @@
+def load_json(filename):
+    with open(filename) as json_file:
+        data = json.load(json_file)
+    return data

git-svn

• The following three commands will import a remote svn repository into a local git repository:

$ mkdir pymmlib && cd pymmlib
$ git svn init -t tags -b branches -T trunk https://pymmlib.svn.sourceforge.net/svnroot/pymmlib
$ git svn fetch

Gitconfig

• Example:

$ cat ~/.gitconfig
[user]
    name = Christoph Champ
    email = someone@somewhere.com
[push]
    default = simple
[alias]
    lg1 = log --graph --abbrev-commit --decorate --date=relative --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)' --all
    lg2 = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset)%C(bold yellow)%d%C(reset)%n''          %C(white)%s%C(reset) %C(dim white)- %an%C(reset)' --all
    lg3 = log --graph --abbrev-commit --decorate --all \
          --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(dim white) - %an%C(reset) %C(bold green)(%ar)%C(reset)%C(bold yellow)%d%C(reset)%n %C(white)%s%C(reset)'
    lg = !"git lg1"
[url "git@github.com:"]
    insteadOf = https://github.com/

See also

• svn

External links

• Official website
• Git User's Manual, also distributed with Git in Documentation/user-manual.txt
• Git in six hundred words
• Git from the inside out
• git for the confused — extremely in-depth manual/tutorial
• Kernel.org git repositories
• Kernel Hackers' Guide to git
• Git and WhatIsGit at LinuxMIPS wiki
• "The Thing About Git"
• "A Git Horror Story: Repository Integrity With Signed Commits", by Mike Gerwitz