How to use the Git version control system
There are a few ways to learn git online including:
Tips and tricks (courtesy of the CIA)
The "I can never remember that alias I set" Trick
[alias]
aliases = !git config --get-regexp 'alias.*' | colrm 1 6 | sed 's/[ ]/ = /' | sort
The "I forgot something in my last commit" Trick
# first: stage the changes you want incorporated in the previous commit
# use -C to reuse the previous commit message in the HEAD
$ git commit --amend -C HEAD
# or use -m to make a new message
$ git commit --amend -m 'add some stuff and the other stuff i forgot before'
The "Oh crap I didn't mean to commit yet" Trick
# undo last commit and bring changes back into staging (i.e. reset to the commit one before HEAD)
$ git reset --soft HEAD^
The "That commit sucked! Start over!" Trick
# takes staged changes and 'stashes' them for later, and reverts to HEAD.
$ git stash
# creates new branch and switches to it, then takes the stashed changes and stages them in the new branch. fancy!
$ git stash branch new-branch-name
The "OK, which commit broke the build!?" Trick
# Made lots of local commits and haven't run any tests...
$ [unittest runner of choice]
# Failures... now unclear where it was broken.
# git bisect to rescue.
$ git bisect start # to initiate a bisect
$ git bisect bad # to tell bisect that the current rev is the first spot you know was broken.
$ git bisect good <some tag or rev that you knew was working>
$ git bisect run [unittest runner of choice]
# Some runs.
# BLAMO -- git shows you the commit that broke
$ git bisect reset #to exit and put code back to state before git bisect start
# Fix code. Run tests. Commit working code. Make the world a better place.
The "I have merge conflicts, but I know that one version is the correct one" Trick, a.k.a. "Ours vs. Theirs"
# in master
$ git merge a_branch
CONFLICT (content): Merge conflict in conflict.txt
Automatic merge failed; fix conflicts and then commit.
$ git status -s
UU conflict.txt
# we know the version of the file from the branch is the version we want.
$ git checkout --theirs conflict.txt
$ git add conflict.txt
$ git commit
# Sometimes during a merge you want to take a file from one side wholesale.
# The following aliases expose the ours and theirs commands which let you
# pick a file(s) from the current branch or the merged branch respectively.
#
# N.b. the function is there as hack to get $@ doing
# what you would expect it to as a shell user.
# Add the below to your .gitconfig for easy ours/theirs aliases.
# ours = "!f() { git checkout --ours $@ && git add $@; }; f"
# theirs = "!f() { git checkout --theirs $@ && git add $@; }; f"
Split a subdirectory into a new repository/project
$ git clone ssh://stash/proj/mcplugins.git
$ cd mcplugins
$ git checkout origin/master -b mylib
$ git filter-branch --prune-empty --subdirectory-filter plugins/mylib mylib
$ git push ssh://stash/proj/mylib.git mylib:master
Local branch cleanup
# Delete local branches that have been merged into HEAD
$ git branch --merged | grep -v '\\*\\|master\\|develop' | xargs -n 1 git branch -d
# Delete local branches that have been merged into origin/master
$ git branch --merged origin/master | grep -v '\\*\\|master\\|develop' | xargs -n 1 git branch -d
# Show what local branches haven't been merged to HEAD
$ git branch --no-merged | grep -v '\\*\\|master\\|develop'