an introduction to git

Transcription

1 gist /"jist/ n [AF, it lies, fr. gisir to lie, ultim. fr. L jacēre more at ADJACENT] (ca. 1711) 1 : the ground of a legal action 2 : the main point or part : ESSENCE <the of an argument> 1 git /"git/ n [var. of get, term of abuse, fr. 2 get] (1929) Brit : a foolish or worthless person 2 git dial var of GET git-go var of GET-GO git tern /"gi-t@rn/ n [ME giterne, fr. MF guiterne, modif. of OSp guitarra guitar] (14c) : a medieval guitar an introduction to git Antonio Cervone February 29, 2012 Merriam-Webster s Collegiate Dictionary, p.529

2 A Distributed RCS Git is a distributed revision control system with an emphasis on speed. Git was initially designed and developed by Linus Torvalds for Linux kernel development. Every Git working directory is a full-fledged repository with complete history and full revision tracking capabilities, not dependent on network access or a central server.

3 Start up configure general information git config --global user.name="<your Name>" git config --global \ > user. =<name@polimi.it> view configuration (local & global) ant@mox> git config --list

4 Create/clone a remote repo ant@mox> git init or from a remote source ant@mox> git clone \ > <username>@cmcsforge.epfl.ch:/gitroot/lifev/lifev autotools stuff ant@mox> cd lifev ant@mox> git clone \ > <username>@cmcsforge.epfl.ch:/gitroot/lifev/admin

5 Protocols PROTOCOL PORT READ WRITE PUBLIC ssh 22 YES YES NO git 9418 YES YES YES/NO http 80 YES NO YES not exclusive!

6 Edit! modify the files in the repo edit the sources... show status of the repo git status # On branch <branch_name> # Changes to be committed: # (use "git reset HEAD <file>..." to unstage) # # modified: file1.cpp # # Changed but not updated: # (use "git add <file>..." to update what will be committed) # (use "git checkout - <file>..." to discard changes in working directory) # # modified: file2.cpp # # Untracked files: # (use "git add <file>..." to include in what will be committed) # # file3.cpp

7 Commit show differences with previous state git diff <branch> <files> stage files for a commit ant@mox> git add <edited_files> create a new commit ant@mox> git commit... <vim editor will come up, write a description for the commit>

8 Get other branches list local branches git branch b1 * b2 master list remote branches ant@mox> git branch -r list all branches ant@mox> git branch -a LifeV branch name policy YYYYMMDD_<meaningful_name>

9 Branching create create new branch ant@mox> git branch <shiny_new_branch> ant@mox> git checkout <shiny_new_branch> or ant@mox> git checkout -b <shiny_new_branch>

10 Branching delete delete a branch ant@mox> git checkout master ant@mox> git branch -d <branch_to_delete> will cause an error if not merged with master! to delete without merging ant@mox> git branch -D <branch_to_delete> delete a remote branch ant@mox> git push origin :<branch_to_delete> the syntax comes from the generic generic push command git push <remotename> <localbranch_name>:<remotebranch_name> so we push an empty branch into the remote branch to be deleted

11 Branching merge merge a branch ant@mox> git checkout master ant@mox> git merge <branch_name> Updating e0f73f9..cd928c7 Fast-forward

12 Branching merge merge a branch ant@mox> git checkout master ant@mox> git merge <branch_name> Updating e0f73f9..cd928c7 Fast-forward conflicts may arise! CONFLICT (content): Merge conflict in file.cpp Automatic merge failed; fix conflicts and then commit the result.

13 Branching solve conflicts 1 manual <<<<<<< HEAD... =======... >>>>>>> branch_name

14 Branching solve conflicts 1 manual <<<<<<< HEAD... =======... >>>>>>> branch_name text editor/gui ant@mox> git mergetool merge tool candidates: meld opendiff kdiff3 tkdiff xxdiff tortoisemerge gvimdiff diffuse ecmerge p4merge araxis emerge vimdiff

15 Branching solve conflicts 2 after the diff are removed ant@mox> git add file.cpp a commit is needed when all the conflicts are solved! ant@mox> git commit

16 Branching stash checkout with hanging modifications is forbidden! ant@mox> git checkout master error: Your local changes to the following files would be overwritten by checkout:... we can stash modifications ant@mox> git stash save and bring them back ant@mox> git stash { pop apply } remember to clear the stash! ant@mox> git stash list ant@mox> git stash clear

17 Collaboration - remote share a branch with a remote repo ant@mox> git push <repo_name> <branch_name> ant@mox> git pull <repo_name> <branch_name> setup remote link ant@mox> git config branch.<branch_name>.remote \ > <repo_name> ant@mox> git config branch.<branch_name>.merge \ > refs/heads/<branch_name> the others can access the branch with alessio@mox> git checkout <branch_name> nur@mox> git checkout --track -b <branch_name> \ > <repo_name>/<branch_name>

18 Collaboration - local share a branch locally nur@mox> git remote add ant_repo \ > /path/to/ant/git/repo nur@mox> git fetch ant_repo nur@mox> git checkout --track -b shared_branch \ > ant_repo/my_super_secret_branch push modifications to the original branch nur@mox> nur@mox> git checkout shared_branch git push ant_repo shared_branch or pull them from the original repo ant@mox> git remote add nur_repo /path/to/nur/git/repo ant@mox> git fetch nur_repo /path/to/nur/git/repo ant@mox> git checkout my_super_secret_branch ant@mox> git pull nur_repo/shared_branch check for read/write permissions!

19 Common issues - I Q edited on master branch

20 Common issues - I Q A edited on master branch a simple checkout will do it ant@mox> git checkout -b new_branch

21 Common issues - I Q A edited on master branch a simple checkout will do it ant@mox> git checkout -b new_branch Q already committed to master branch

22 Common issues - I Q A edited on master branch a simple checkout will do it ant@mox> git checkout -b new_branch Q already committed to master branch A create a new branch and delete the commit on master ant@mox> git branch new_branch ant@mox> git reset --hard HEAD~1 ant@mox> git checkout new_branch

23 Common issues - II Q commit in wrong branch

24 Common issues - II Q A commit in wrong branch cherry-pick it to the correct one ant@mox> git checkout correct_branch ant@mox> git cherry-pick commit_hash

25 Common issues - II Q A commit in wrong branch cherry-pick it to the correct one ant@mox> git checkout correct_branch ant@mox> git cherry-pick commit_hash Q cannot get the branch of the local remote

26 Common issues - II Q A commit in wrong branch cherry-pick it to the correct one ant@mox> git checkout correct_branch ant@mox> git cherry-pick commit_hash Q A cannot get the branch of the local remote missing references to the other branches ant@mox> git fetch remote_name ant@mox> git remote show remote_name

27 Common issues - III Q the merge has gone bananas!

28 Common issues - III Q A the merge has gone bananas! give up the merge and try again ant@mox> git merge <branch_to_be_merged> ant@mox> #$!&#%$&ˆ ant@mox> git reset --hard <original_branch>

29 Common issues - III Q A the merge has gone bananas! give up the merge and try again ant@mox> git merge <branch_to_be_merged> ant@mox> #$!&#%$&ˆ ant@mox> git reset --hard <original_branch> Q i want a file from that branch!

30 Common issues - III Q A the merge has gone bananas! give up the merge and try again ant@mox> git merge <branch_to_be_merged> ant@mox> #$!&#%$&ˆ ant@mox> git reset --hard <original_branch> Q A i want a file from that branch! get it or adopt a merge strategy ant@mox> git checkout <branch> <files> ant@mox> git merge <branch> -X <ours/theirs/... >

31 Common issues - IV Q git push refuses to work remote: error: refusing to update checked out branch: refs/heads/<branch_name> remote: error: By default, updating the current branch in a non-bare repository remote: error: is denied, because it will make the index and work tree inconsistent remote: error: with what you pushed, and will require git reset -hard to match remote: error: the work tree to HEAD. remote: error: remote: error: You can set receive.denycurrentbranch configuration variable to remote: error: ignore or warn in the remote repository to allow pushing into remote: error: its current branch; however, this is not recommended unless you remote: error: arranged to update its work tree to match what you pushed in some remote: error: other way. remote: error: remote: error: To squelch this message and still keep the default behaviour, set remote: error: receive.denycurrentbranch configuration variable to refuse. To <repo>! [remote rejected] <branch_name> -> <branch_name> (branch is currently checked out)

32 Common issues - IV Q git push refuses to work remote: error: refusing to update checked out branch: refs/heads/<branch_name> remote: error: By default, updating the current branch in a non-bare repository remote: error: is denied, because it will make the index and work tree inconsistent remote: error: with what you pushed, and will require git reset -hard to match remote: error: the work tree to HEAD. remote: error: remote: error: You can set receive.denycurrentbranch configuration variable to remote: error: ignore or warn in the remote repository to allow pushing into remote: error: its current branch; however, this is not recommended unless you remote: error: arranged to update its work tree to match what you pushed in some remote: error: other way. remote: error: remote: error: To squelch this message and still keep the default behaviour, set remote: error: receive.denycurrentbranch configuration variable to refuse. To <repo>! [remote rejected] <branch_name> -> <branch_name> (branch is currently checked out) A use a bare repo ant@mox> git clone -bare <repo> <repo>.git

33 Tips & tricks - I gitk is your friend

34 Tips & tricks - I gitk is your friend do small, atomic commits

35 Tips & tricks - I gitk is your friend do small, atomic commits read git output

36 Tips & tricks - I gitk is your friend do small, atomic commits read git output branch in PS1 : add to.bashrc function GitBranch { _branch="$(git branch 2>/dev/null sed -e "/^\s/d" -e "s/^\*\s//")" test -n "$_branch" && echo -e "@$_branch" } PS1='\u@\h:\w$(GitBranch)> '

37 Tips & tricks - I gitk is your friend do small, atomic commits read git output branch in PS1 : add to.bashrc function GitBranch { _branch="$(git branch 2>/dev/null sed -e "/^\s/d" -e "s/^\*\s//")" test -n "$_branch" && echo -e "@$_branch" } PS1='\u@\h:\w$(GitBranch)> ' watch out for non history-safe commands after pushing! ( cherry-pick, rebase,... )

38 Tips & tricks - I gitk is your friend do small, atomic commits read git output branch in PS1 : add to.bashrc function GitBranch { _branch="$(git branch 2>/dev/null sed -e "/^\s/d" -e "s/^\*\s//")" test -n "$_branch" && echo -e "@$_branch" } PS1='\u@\h:\w$(GitBranch)> ' watch out for non history-safe commands after pushing! ( cherry-pick, rebase,... ) everything else (and more... ) on git

39 Tips & tricks - II bash autocompletion contrib/completion/git-completion.bash;hb=head

40 Tips & tricks - II bash autocompletion contrib/completion/git-completion.bash;hb=head colored output ant@mox> git config --global color.ui true

41 Tips & tricks - II bash autocompletion contrib/completion/git-completion.bash;hb=head colored output ant@mox> git config --global color.ui true no empty push ant@mox> git config --global push.default nothing

42 Tips & tricks - II bash autocompletion contrib/completion/git-completion.bash;hb=head colored output ant@mox> git config --global color.ui true no empty push ant@mox> git config --global push.default nothing creating archives ant@mox> git archive <commit_or_branch> gzip > \ > <archive_name>.tgz