Git(hub) Cheat Sheet
I am posting my github cheat sheet here. I started writing it as soon as I started learning Github and Git. So, some of the content here can appear quite naive. I will try to keep this blog post as updated as I can, and if you find any suggestion, please comment!
This post is just for a reference of commands. This post will be a bad way to learn how git works. A basic understanding of git is assumed.
##Initial configuration Configure user details only for the first time
git config --global user.name "Rushi Agrawal"
git config --global user.email "rushi.agr@gmail.com"
To check your git configuration
git config --list
##Branches List all branches in the local repo
git branch
List all branches including remote-tracking branches
git branch -r
List all branches (including the ones at remote)
git branch -a
Creating your own branch my_branch, with content same as your current branch
git branch my_branch
Switch to the newly created branch
git checkout my_branch
Execute the above two commands in one line:
git checkout -b my_branch
to pull a branch only_remote which exists at github (at remote rushiagr but not in local repo. (More about git remote update later)
git remote update
git checkout -b only_remote rushiagr/only_remote
Remotes
Create a new remote rushiagr which will track cinder repository by user rushiagr
git remote add rushiagr https://github.com/rushiagr/cinder.git
If this is your personal repo, you can append the username in the remote as shown. After that, every time you push to the origin, github will not ask for your username but only password.
git remote add rushiagr https://rushiagr@github.com/rushiagr/cinder.git
Delete the remote rushiagr
git remote rm rushiagr
List all the remotes
git remote
The above command only shows the names of remotes. To also check the links to the remotes:
git remote -v
Now this is very important command.
git remote update
This will contact the git server, and will update the local repository with ALL the content at ALL those remotes. The interesting part is, nothing will actually change. That is, no more new branches (which got created at the server after you last pulled from the server) were created, and the existing branches are also not updated. BUT, all the content goes into the magic .git directory. After you've run this command, when you create a branch only existing at remote, the local git repo will not contact the server but will fetch all the contents from within the repository.
To take a new branch from remote, and create a new branch having contents of that remote branch. (You might need to run ‘git remote update’)
git checkout -b stable/folsom origin/stable/folsom
Push
Pushing this newly created branch to remote rushiagr
git push rushiagr my_branch
If you want to push the local branch my_branch with a different name to
remote, say my_remote_branch:
git push rushiagr my_branch:my_remote_branch
To create an association with the remote (only first time):
git push -u origin my_branch
or
git push --set-upstream origin my_branch
Pull
Git pull is nothing more than a macro that does git fetch and git merge, in
that order. The common syntax to pull from branch remote_branch located at remote remote_name to the current active branch in the local repo:
git pull remote_name remote_branch
Oops! I didn't intend to do that!
####To undo last commit. This will just undo the commit, but will keep changes, so that you can modify the files and commit again
git reset --soft HEAD^
####To not keep the uncommitted changes.
This command will wipe off all the changes which are not committed. Very useful when you made some changes but dont want to commit it. All the more useful when you pulled something but everything became a mess (possibly due to a merge conflict, or pulling to/from a different branch!)
git reset --hard
####To delete a branch timepass_testing from github server
git push rushiagr --delete timepass_testing
(NOT git push rushiagr --delete rushiagr/timepass_testing)
####Change author of the last commit
git commit --amend --author="Rushi Agrawal <rushi.agr@gmail.com>"
You committed some changes, but then you realised you wanted to add this one line to the commit. In such a case just add that one line, and run this command to have this last change incorporated into that previous commit. This command also gives you an option to change the commit message.
git commit -a --amend
Show me the money
To see the patch of the last commit without undoing the last commit
git show
To see the changes introduced by any earlier commit with commit id c5bb6d821e10ca8f114fa0b3b0149bc8b7257a92
git show c5bb6d821e10ca8f114fa0b3b0149bc8b7257a92
To see the latest changes you made – the changes which have not been staged to be committed
git diff
You can redirect the output from the above three commands to a file, to create corresponding patch file.
Patching in git
Check the status of patch. How many lines changed, etc
git apply --stat patchfile
Check if the patch can be applied. If no output or no error, patch can be applied safely
git apply --check patchfile
Apply patch with signing-off (better way)
git am --signoff < patchfile
Normal way of applying patch
git apply patchfile
##Miscellaneous
To pull only specific files from another branch: (here, assuming that we have two branches, ‘test’, and ‘master’, and currently we are on ‘master’ branch. If you want to pull ##only ‘testfile.py’ file from ‘test’ branch to ‘master’ branch, do this:)
git checkout test testfile.py1
If your master changed while you were working on your topic_branch, and if you want to merge the master's changes, and also get an option to squash the changes you made on topic_branch:
git checkout master
git pull origin master
git checkout topic_branch
git rebase -i master
Undo last commit at the remote repo
(you can use git revert, but don’t know how exactly it works)
Clone a specific branch git repository from github
git clone -b stable/essex https://github.com/openstack-dev/devstack.git
Squash several commits into one single commit
Checkout a previous commit with SHA commit id cff2580ad7bc16934b72dd9be7463eb090b31d55 from the current branch to a new branch ‘neew’
git checkout -b neew cff2580ad7bc16934b72dd9be7463eb090b31d55