SamatsWiki

• Diff for "CheatSheet/Git"

See also: CodingStyle/Git

Workflow for gitorious and github

Initial checkout:

   1 # Fork repo on gitorious/github
   2 # Pull repo from gitorious/github
   3 # Add remote for upstream, e.g.
   4 cd Spoon-Knife
   5 git remote add upstream git://github.com/octocat/Spoon-Knife.git
   6 git fetch upstream

See Configuring a remote for a fork

When needing to merge upstream changes back into master:

   1 # Make sure we're in the branch we want to be in (i.e. master)
   2 git checkout master
   3 git fetch upstream
   4 # Merge from master branch of upstream into current branch
   5 git merge upstream/master

Cookbook

Delete remote branch

git push origin :name-of-remote-branch
# OR
git push origin --delete name-of-remote-branch

Reverting changes

Amend the previous commit that has not been propogated (i.e. undo it, then start a new one with the pending changes in the index):

git commit --amend -a -m "New commit message"

Undo a commit that has not been propagated:

git reset --soft HEAD^

just changes the repository without changing the files you've edited on disk. However:

git reset --hard HEAD^

will reset both repository and revert files.

Once a commit that has been propagated, there is no way to undo. However, the following will create a new commit undoing the previous commit's changes:

git revert HEAD

To only change a commit message for a commit that has not been propogated:

git commit --amend

Pull with rebase instead of merge

git pull --rebase

Configure a branch to always do a rebase instead of a merge:

git config branch.$BRANCH_NAME.rebase true

Enforce .gitignore

Remove files from the repository that should have been ignored by .gitignore:

git rm -r --cached .
git add .
git status
git commit -m ".gitignore is now working"

Search

# Search commit log (i.e. messages) for given needle in all branches
git log --all --grep='needle'
# As above, but search reflog (much slower)
git log -g --grep='needle'
# Search contents of commits
git grep -F 'needle' $(git rev-list --all)
# Search contents of commit in a large repository
git rev-list --all | parallel -j4 -k -X git grep --color=always -F 'needle'
# Search branches (has problems)
git branch -a | tr -d \* | parallel -k git grep --color=always -iF 'needle'

Ignore whitespace bullshit

# Ignore white space when pulling or merging
git pull -Xignore-space-change
git merge -Xignore-space-change
git merge -Xignore-all-space

# Ignore white space changes when diff'ing
git diff --ignore-space-change

Rebase a branch

# Without having branch-you-want-to-rebase checked out
git rebase branch-you-want-to-rebase branch-to-rebase-from
# With having branch-you-want-to-rebase checked out
git checkout branch-you-want-to-rebase
git rebase branch-to-rebase-from

Rebase off a branch that itself had been rebased (keep the un-rebased branch around as old-branch-to-rebase-from):

git rebase --onto branch-to-rebase-from old-branch-to-rebase-from branch-you-want-to-rebase

If you want to rebase but get updated stamps (do this independently of reordering/merging commits with git rebase -i:

git rebase --ignore-date

Interactive rebase

Interactive rebase for only certain commits:

# Rebase only the last 2 commits
git rebase -i HEAD~2
# All commits that are on feature branch, but not on trunk branch
git rebase -i trunk

Retroactively sign all previous commits

Uses rebase, so this will invalidate other checkouts.

git rebase --exec 'git commit --amend --no-edit --no-verify -S' -i --root
git rebase --committer-date-is-author-date -i --root
# check
git log --pretty=fuller

Source: Git sign previous commits keeping dates by Peter Babič

Problems

Cannot lock ref error

error: cannot lock ref 'refs/remotes/origin/bugfix/SPL-178301-lookups-cache-results-incorrectly':

is caused by your local repository's copy of the origin repository's branches getting corrupted. To fix:

git remote prune origin

It will not touch any of your local branches with your edits, or anything remote, just your local repo's knowledge of remote branches.

Per-repository user settings

git config user.name 'Samat K Jain'
git config user.email 'nobody@example.com'

Cleaning

# Discard all unstaged changes in CWD
git checkout -- .
# Remove untracked files and directories, dry run. `-n` for dry run.
git clean -df -n

GPG Signing

   1 # GPG sign all previous commits. Careful!
   2 git filter-branch -f --commit-filter 'git commit-tree -S "$KEY_ID"' HEAD

Submodules

In the below, TARGET_DIR is something like vendor/some-package.

Cloning a project w/ submodules

First clone:

git clone --recurse-submodules …

If you forgot --recurse-submodules, can run:

git submodule update --init --recursive

Adding submodules to a project

git submodule add $REPOSITORY_URL $TARGET_DIRECTORY

You need to start tracking the new .gitmodules file (just like .gitignore), as well as a "file" representing the submodule. git status will show it as $TARGET_DIRECTORY.

git add .gitmodules $TARGET_DIRECTORY
git commit -m 'Started tracking $REPOSITORY_URL as submodule'

Update submodules

Go to each submodule, fetch, and update:

git submodule update --remote --recursive
# git commit

Remove submodules

Go to each submodule, fetch, and update:

git submodule rm $TARGET_DIR
# git commit
# Completely remove submodule (will need to be init again if you go backwards in history) to save disk space
rm -Rf .git/modules/$TARGET_DIR

Will be done with a git pull automatically if submodule.recurse option is True.

Misc

Tell git to track a specific branch of a submodule, e.g. "master":

git config -f .gitmodules submodule.${TARGET_DIR}.branch master
# commit .gitmodules

-f is specified so that .gitmodule can be updated and other people using the repository can track the same branch. Omit this if you don't care.

Settings

# `--recursive` for everything but `git clone`
git config --global submodule.recurse true
# Show summary of submodule changes in `git status`
git config --global status.submodulesummary true
# Prettier diff for submodules
git config --global diff.submodule log

Interesting reading

The Git Parable: Describes building a system like git, from the ground-up

CIA's git tips & tricks sheet is interesting, and oddly similar to this one.

git-email-based workflow

An e-mail-based workflow is preferred by many projects, including the Linux kernel.

• Git email flow vs Github flow

• git-send-email.io helps you get up and running w/ git-email

CategoryCheatSheet