git stuff - naughtont3/techbits GitHub Wiki

Git Related Stuff

Syncing a fork with upstream (using Open MPI as example)

NOTE: Assumes remotes are:
- "remotes/origin" is my fork
- "remotes/upstream" is original
NOTE: For safety I always set the upstream push as bogus. git remote set-url upstream bogus --push (Thanks JeffS!)

    $ cd ompi/
    $ git remote
    origin
    upstream
    $ git remote -v
    origin	https://github.com/naughtont3/ompi.git (fetch)
    origin	https://github.com/naughtont3/ompi.git (push)
    upstream	https://github.com/open-mpi/ompi.git (fetch)
    upstream	bogus (push)
    $ git fetch upstream
    $ git checkout master
    $ git merge upstream/master
    $ git push origin master

    ###
    # NOTE: To rename the branch
    #   git push <REMOTE-NAME>  <LOCAL-BRANCH>:<REMOTE-BRANCH>
    #   git push origin        foobar-localhacks:foobar
    ###

Refs:
- https://help.github.com/articles/syncing-a-fork/
- https://help.github.com/articles/pushing-to-a-remote/

Cache credentials (avoid username/password prompt) stackoverflow

 git config credential.helper store
 git pull
 # Enter username/password (cached next time)

Update a forked repo (steps from https://gist.github.com/CristinaSolana/1885435)

Clone your fork:

git clone [email protected]:YOUR-USERNAME/YOUR-FORKED-REPO.git

Add remote from original repository in your forked repository:

 cd into/cloned/fork-repo
 git remote add upstream git://github.com/ORIGINAL-DEV-USERNAME/REPO-YOU-FORKED-FROM.git
 git fetch upstream

1. Updating your fork from original repo to keep up with their changes:
```
 git pull upstream master
```

Show differences between two branches

    # Color based summary (master vs. tjn-fy15-orbit branch)
   git diff --stat --color master..tjn-fy15-orbit

    # Concise 'svn status' style summary (master vs. tjn-fy15-orbit branch)
   git diff --name-status  master..tjn-fy15-orbit

Restore previously deleted file (e.g., SetupVagrant.md)

Find the last revision that touched it

git rev-list --max-count=1 --all -- SetupVagrant.md
8dd9a1c5e962ad5cc5d952aacfcef35a69e3574b

1. To see contents of the file in previous-1 revision (just before last touch)
```
 git show 8dd9a1c5e962ad5cc5d952aacfcef35a69e3574b~1:SetupVagrant.md
```

Checkout the last version where it occurred (then add/commit/push)

 git checkout 8dd9a1c5e962ad5cc5d952aacfcef35a69e3574b~1 SetupVagrant.md

Selectively add changes (patch based add)
```
 git add -p file.c
```
Show "remote" repos
```
 git remote -v
```

Create a secondary ("alternate") remote repo

 git remote add tjnalt <URL_FOR_REMOTE>

Example:

 $ git add tjnalt https://github.com/naughtont3/ompi.git
 $ git remote -v
 origin  https://github.com/open-mpi/ompi.git (fetch)
 origin  https://github.com/open-mpi/ompi.git (push)
 tjnalt  https://github.com/naughtont3/ompi.git (fetch)
 tjnalt  https://github.com/naughtont3/ompi.git (push)

Push changes to an "alternate" remote repo
```
 git push -u tjnalt my-branch-name
```

Clone central repo and then track bracn in an "alt" repo

 git remote add tjnalt <REPO-PATH>
 git remote -v
 git branch -a
 git fetch tjnalt
 git branch -a
   # See new branches of other remote
 git checkout -t -b tjn-new-feature-1 tjnalt/tjn-new-feature-1
   # now our 'tjn-new-feature-1' branch is local and tracking upstream ('tjnalt') repo

Integration of branch changes to master branch (steps)

 git checkout master
 git pull --rebase
 git checkout -b tjn-master-feature1-int
 git branch -a
   # see that we are now in integration branch 'tjn-master-featureFoo1-int'

   # merged our featureFoo1 branch into integration branch 
 git merge tjn-featureFoo1

Tagging: Show tags
```
 git tag -l 
```
Tagging: Create a tag
```
 git tag -a v1.4 -m "my version 1.4"
```

Pull-Request: Fetch a pending pull-request (PR) for local testing

 git fetch origin pull/<PR#>/head:pr-<PR#>-mybranch
 git checkout pr-<PR#>-mybranch

Setup Name and Email for Git usage (see also: $HOME/.gitconfig)

 git config --global user.name "John Public"
 git config --global user.email "[email protected]"

Commit Signoff (requires Name/Email setup)
```
 git commit --signoff
```
Commit Signoff for previously commited change (requires Name/Email setup)
```
 git commit --amend --signoff
```
- NOTE Results in a new commit hash (SHA#) so exercise care with public contributions. If already pushed to remote repository, then will require a --force push. Generally should avoid force pushes on ANY publicly shared changes.
Cherry picking
```
 git cherry-pick -b newbranch <SHA#>
```
- NOTE Cherry-picking changes the commit hash (SHA#), resulting in a new/different commit hash (SHA#). Therefore these are only manually identifable by commit message or close inspection of changeset. (Changes are different git commits!)

Rebasing a pull-request

 git checkout pr/my-bugfix-branch
 git rebase -i origin/master
   # Now our 'bugfix' branch has been updated (interactively) to
   # be updated with latest master

Rebasing during pull (Fast-Forward a branch)

  # Pull but fast-forward our branch's changes to tip of new changes
 git pull --rebase

Make default origin read-only (to avoid accidentally pushing to wrong repo)

 git remote set-url origin bogus --push
 git remote -v
 origin https://github.com/open-mpi/ompi.git (fetch)
 origin bogus (push)
 tjnalt https://github.com/open-mpi/ompi.git (fetch)
 tjnalt https://github.com/open-mpi/ompi.git (push)

Delete local branches (that are no longer at remote origin repo)

 git remote prune origin

Related from JSquyres:

 git fetch --all --prune
  # Jeff made this into an alias 'fap' (Fetch-all-Prune) in ~/.gitconfig

Delete remote branches from the command-line (not have to use Web to remove branch)

  git push origin --delete mydev-foobar7

Example...

    # -BEFORE-
    # git br -a
    # * master
    #   remotes/origin/mydev-foobar7
    #   remotes/origin/master
  git push origin --delete mydev-foobar7
    # -AFTER-
    # git br -a
    # * master
    #   remotes/origin/master

Reword/rework commits (squashing!)

  # Reword/squash last 3 commits
git rebase -i HEAD~3

Set master tracking

 git checkout master
 git br --set-upstream-to origin

Show history for specific line(s) stackoverflow ref

Requires Git >=1.8.4

     # Show lines 110 to 110+2 of given file
   git blame -L 110,+2:src/mca/rmaps/base/base.h

git stuff - naughtont3/techbits GitHub Wiki

Git Related Stuff

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