Git recipes

This page is made to give useful command or succession of commands to perform Git tasks in the context of the CamiTK Git workflow.

We also recommend you to check these extra 15 Git tips to improve your workflow.

This is a small collection of little recipes for current git operations.

Undo, cancel, cleanup

Undo/Cancel the last commit

Simply use this command to completely undo the last commit and erase history.

git reset --hard HEAD~1

You can also simply use this command to undo the last commit but leave the history (and your files):

git reset --soft HEAD~1

Undo (uncommitted) changes

For instance, you have accidentally removed a file. To revert changes to modified files:

# Be careful: it resets the index and working tree. Any changes to tracked files in the working tree since the last commit are discarded.
git reset --hard

This is the same as git reset –hard HEAD.

Clean the current working tree

Use with care

# check first what is going to happen
git clean -nd
# if ok, do it, f=force, d=remove directories
git clean -fd

List the files modified by the last commit

Just type:

git log -n 1 --name-only --pretty=full

Working with branches

Rename a branch

git branch -m compile-on-sid <newName>

Diff between two branches

There are a lot of different ways to compare branches:

git diff b1..b2
git diff b1...b2
git log b1..b2
git shortlog b1..b2

To get only the filenames that have changed:

git diff --name-status b1..b2

See this stackoverflow answers

Copy commits from one branch to the current branch

Just type:

git cherry-pick commit-hash

To apply the commit commit-hash (made on another branch) to your current branch.

It is also possible to copy a range of commits from one branch to the current branch.

List all local branches and display last modified dates

From stackoverflow

for k in `git branch | sed s/^..//`; do echo -e `git log -1 --pretty=format:"%Cgreen%ci %Cblue%cr%Creset" $k --`\\t"$k";done | sort

Solve a conflict after a pull

Just type:

git mergetool

Running git mergetool will prompt the user for each conflict, and propose a default application. On Linux, we recommend to use kdiff3 as the git diff tool.

Miscellaneous

Set VIM as default message editor

git config --global core.editor "vim"
export GIT_EDITOR=vim

Visualize Git tree under Linux

If git is not directly integrated in your IDE, for linux developers we recommend qgit

In order to get qgit:

sudo apt-get install qgit
qgit

If your distrib does not have the package yet, get the source code at https://github.com/feinstaub/qgit .

Otherwise you can do this for git-cola :

sudo apt-get install git-cola
git-cola

Switch from git@ protocol to https:// protocol

This might be useful when you develop on another machine (not your regular workstation) and you don’t really want to copy your ssh key to this (not so trusted) machine. If you have clone the git repository with the https://, you have nothing to do. But if you used the git@ protocol, as it uses the ssh protocol, you have to configure your local ~/.ssh to interact with the origin repository. You may easily switch from git@ protocol to https:// protocol by typing:

git config --global url."https://yourgitserver.example.com/".insteadOf git@/yourgitserver.example.com:
git config --global url."https://".insteadOf git://

For instance, if your git repository is hosted on the same gitlab instance as the CamiTK Community Edition, the following will do the trick:

git config --global url."https://gricad-gitlab.univ-grenoble-alpes.fr/".insteadOf git@/gricad-gitlab.univ-grenoble-alpes.fr:
git config --global url."https://".insteadOf git://

You can check that everything is in order by typing:

cat ~/.gitconfig

Troubleshooting

pathspec did not match any file

If you get the following error:

git checkout name-of-branch-on-origin
error: pathspec 'name-of-branch-on-origin' did not match any file(s) known to git

First try git fetch to update your local git repository.

If this does not work, it might be that you cloned only a specific branch (using the -b develop git clone parameter for instance). In this case, git fetch won’t help as the local repository is only aware of the develop branch. You can check that by typing git config --get remote.origin.fetch. If it displays +refs/heads/develop... you are in this case.

In order to be able to get any other available branch from origin, type:

git config remote.origin.fetch "+refs/heads/*:refs/remotes/origin/*"

(note the * instead of develop)

Then type git fetch to update your local git repository. It should shows the list of new available branch that you can now checkout locally.

Git recipes related to CamiTK

Clone to contribute

First, you need to clone the CamiTK git repository and switch to develop branch (see also the install pages).

If you want to share your work, you first need to create an account on our gitlab instance. We advised to login (if you are with the University Grenoble Alpes) or create a guest account first and then add an ssh key.

# R/W clone
git clone git@gricad-gitlab.univ-grenoble-alpes.fr:CamiTK/CamiTK.git

Delete local branches once they are merged

To delete all local branches that were merged on origin:

git fetch -p && git branch -vv | awk '/: gone]/{print $1}' | xargs git branch -D

Working on a feature branch

To version your code, do not hesitate to commit to your branch as often as possible (and to push it so that your changes can appear in the merge request for review or sharing). When you push, the gitlab-ci system is automatically started unless you add [ci skip] or [skip ci] to the commit message. You can also use git push -o ci.skip to prevent CI pipelines from running see gitlab doc.

Updating a feature branch that have conflicts with current develop

Sometimes your feature branch will be to distant to develop. In this case, gitlab will complain and say that you can not merge your feature branch in develop. In this case DON’T FOLLOW the instructions given by gitlab. It is better to do the following steps :

# First update your local develop branch
git checkout develop
# Get the current remote version 
git fetch -p origin
# Merge the changes from `origin/develop` into your local `develop` branch. Your local `develop` branch will then be in sync with the remote repository
git merge origin/develop
# Check out your feature branch
git checkout feature/new-feature
# Merge the updated `develop` into your feature branch to include the latest changes
git merge develop

Now you can solve the conflicts. Note for Linux user, we recommend using a GUI merge tool to help to solve the conflicts, for instance:

git mergetool --tool=kdiff3

This only updates the local feature branch. Then, you need to:

• check all the files (some automatic merges might not be what you want)
• if needed, add and commit your changes (e.g. git add .; git commit -m "Solved merge conflicts")

Push you branch to remote:

git push origin feature/new-feature

Gitlab should start the CI pipeline and remove the merge conflict warnings.