Difference between revisions of "Git Hacks and Tricks"

From OPeNDAP Documentation
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: # origin  git@github.com:USERNAME/OTHERREPOSITORY.git (fetch)
: # origin  git@github.com:USERNAME/OTHERREPOSITORY.git (fetch)
: # origin  git@github.com:USERNAME/OTHERREPOSITORY.git (push)
: # origin  git@github.com:USERNAME/OTHERREPOSITORY.git (push)
;Amending the commit message
:''git commit --amend''
:''git commit --amend -m "New commit message"''

Revision as of 14:54, 26 June 2015

1 Git resources

2 Setup a username and access token for GitHub

git config --global github.user <name>
git config --global github.token <token>
where the token is made using the instructions at https://help.github.com/articles/creating-an-access-token-for-command-line-use

3 When using an old version of git on Linux

[jimg@wasabi hyrax-git]$ git pull
error: Couldn't resolve host 'github.com' while accessing https://github.com/opendap/hyrax.git/info/refs

4 Cheat sheet items

These are simple things that are not really obvious from the git book or other sources

How to see a list of 'conflicted' files after a merge
git diff --name-only --diff-filter=U
How to see the difference between to commits
git diff <commit-hash-1> <commit-hash-2>, e.g., git diff 0da94be 59ff30c
...for a specific file: git diff <commit-hash-1> <commit-hash-2> -- <file>
...and don't forget the shorthand for the hashes: git diff HEAD^^..HEAD -- main.c where HEAD^ is the parent of HEAD. HEAD{n} is the Nth parent.
How to see the different remote branches
git remote show origin
Fetch all the branches on origin
git fetch origin
How do I list the remote branches (that have been fetched)?
git branch -a
How do I switch to a branch from a remote origin?
git checkout -b test origin/test
or, with newer versions of git: git checkout test
How do I see what would be pushed to a remote repo?
git push --dry-run
git diff origin/master # Assumes you have run git fetch, I think
git diff --stat origin/master # --stat just shows the file names stats, not the diffs
To get a specific file from a specific branch
git show dap4:./gdal_dds.cc > gdal_dds.dap4.cc You can use checkout instead of show and that will overwrite the file.
the general syntax is object (that's the 'dap4:./gdal_dds.cc' part) and it can use the ^ and ~n syntax to specify various commits on the given branch. A SHA can also be used.
How to change the 'origin' for a remote repo
git remote set-url origin git://new.url.here (https URLs work too...)
How to push a local branch to a remote repo
git push -u origin feature_branch_name
How to make and track a new (local) branch
git checkout -b <branch name>
How to track a remote branch
git checkout --track origin/serverfix or git checkout -b sf origin/serverfix
How do I make an existing local branch track an existing remote branch?
git branch --set-upstream-to=upstream/foo foo where upstream is probably actually origin.
Commited my code, then made a bunch of changes that just seem like a bad idea in retrospect. How do I go back to my previous commit for everything in a directory? I don't care if I loose all my changes since the last commit.
git reset HEAD --hard (Note that this is one of the very few git commands where you really cannot undo what you have done).
How to undo a commit (that has not been pushed)
git reset --soft HEAD~1. This leaves the files in their changed state in your working dir so that you can edit them and recommit. You can also change to a different branch and commit there, then change back.
In the above case, To reuse the old commit message
git commit -c ORIG_HEAD <-- This works because 'reset' copied the old head to .git/ORIG_HEAD. If you don't need to edit the old message, use -C instead of -c.
How to delete a remote brnach
git push origin --delete serverfix The data are kept for a little bit - before git runs garbage collection - so it may be possible to undo this.
How to delete a local branch
git branch -d the_local_branch and delete the remote branch you were tracking with the same name git push origin :the_remote_branch
How to I set up a git cloned repo on a remote machine so I don't have to type my password all the time?
This page shows how to make a PKI key-pair with a secure password, configure the machine to remember the password using ssh-agent and upload the public key to your github account so it'll use the key for authentication. https://help.github.com/articles/generating-ssh-keys/
How can I know which branches are already merged into the master branch?
git branch --merged master lists branches merged into master
git branch --merged lists branches merged into HEAD (i.e. tip of current branch)
git branch --no-merged lists branches that have not been merged
By default this applies to only the local branches. The -a flag will show both local and remote branches, and the -r flag shows only the remote branches.
Switching remote URLs from HTTPS to SSH
git remote -v
# origin https://github.com/USERNAME/REPOSITORY.git (fetch)
# origin https://github.com/USERNAME/REPOSITORY.git (push)
git remote set-url origin git@github.com:USERNAME/OTHERREPOSITORY.git
git remote -v
# Verify new remote URL
# origin git@github.com:USERNAME/OTHERREPOSITORY.git (fetch)
# origin git@github.com:USERNAME/OTHERREPOSITORY.git (push)
Amending the commit message
git commit --amend
git commit --amend -m "New commit message"