Git in Production

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git-github/git_in_production.md
Apr 18, 2019
Git & Github

Pretty and concise logs

add an alias

nano ~/.gitconfig

[alias]
	lg = log --color --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --branches

You can now use git lg to see better logs

Change commit message of last commit

git commit --amend

It’ll open the editor and you’ll be able to update the last commit message. Only do this for unpushed code

Add a file i forgot in last commit

git commit --amend

When you run the command it’ll automatically include the newly modified files. Only do this for unpushed code

Update feature with latest changes from master

Get changes from the main development branch.

# switch to master and get latest changes
git checkout master
git pull

# switch to feature and pull changes from master
git checkout feature

# merge is good when you have other devs working on the code 
# and the changes have been committed and pushed
git merge master

# rebase is ok if you're the only dev and as long as you haven't pushed yet
# beware of rebase changing commit hashes
git rebase
  • git merge is recommended when you have a shared branch and other developers are working on it as well
  • git rebase will get all changes from master and merge it on top of your feature branch. Doing so will change the commit hashes.
  • git rebase will rewind head and replay our work on top of it.

Move accidental commits from master to another branch

# Changes haven't been pushed yet, and NOT synced with remote
# otherwise you'll mess up commit history

# create a new branch from master 
# since you have pushed your changes to master the new branch will have those changes
git checkout master
git checkout -b newBranch

# go back to master and remove those accidental changes by going back
# to the point where those commits weren't added
git checkout master
git reset --hard XXXXX

Combine multiple commits into one

git rebase -i  XXX

# select the actions you want to take for every commit, close editor and continue

You’ll get a summary of all the commits from XXX onwards

  • -i is for inetractive
  • XXX is the commit from where you want to start and update commits that came after this point

See the changes in local commits (with diff)

git diff # unstaged changes
git diff --staged # staged changes
git diff HEAD # both staged+unstaged changes
git diff --stat # summary of what files changed, no. of line +/- etc.
git diff --check # check for merge conflicts

Create empty branches

Create the Git branch as an orphan. That means it’ll have no ‘parent’, hence no code. All the code that is there can be removed with git rm --cahced -r .

git checkout --orphan FOO

# multiple ways of removing files.. 
git rm -r --cached .
git reset --hard
git clean -fd

Save dirty copy of your work in progress

git add . # capture all 'Work In Progress' files
git stash # put it away

# la la la, go to other branches, make changes, commit etc.

# go back to the branch you were working in
git stash pop # get it back, remove it from stash

git stash list
git stash apply # get it back, keep the stashed copy as well
git stash apply X # apply the number 'X' stash from your list (e.g. stash@{1})
git stash save 'wip: fancy feature' # stash it with a name
  • pop will take the stash out of git stash list, apply would not.
  • by default apply will get back the the most recent stash

See changes between your file and remote file (with diff)

git diff HEAD myFile.js

compare two different commits

git diff XXXX YYYY

Wipe a commit from local

git reset --hard XXXX
  • will jump back to the XXXX commit discarding all the ones that came after it
  • make sure you’re getting rid of only local commits and that the cahnges haven’t already been pushed

Delete a commit from remote

# find your commit 
git log --oneline 

# reset will checkout the specified commit and remove everything that came after it
git reset --hard XXX

# push your changesto remote
git push --force
# git push origin +develop
  • keep in mind that --hard throws away all your uncommitted changes. to use --hard first make sure the output of git status is clean

Undo commits that have already been pushed to remote (with revert)

git revert XXXX
  • reset and amend will change the commit hash, which we don’t want, as it’ll cause conflicts since the code has already been pushed to remote and other people may have pulledit already.
  • revert does not change the commit hash, which is why it is a good command for getting rid of changes that have already been pushed to remote

See only local unpushed changes in current branch

git log origin/master..HEAD

# you can view diff using the same syntax
git diff origin/master..HEAD

See all local merge conflicts

git status

Squash all commits into one and merge to master

git checkout master
git merge --squash fooBranch