Skip to content

Latest commit

 

History

History
403 lines (294 loc) · 8.96 KB

README.md

File metadata and controls

403 lines (294 loc) · 8.96 KB
Raw

Professional Practice: Git Seminar

Adapted from Nice Reidman's interactive Git tutorial

"Learn git concepts, not commands"

Resources

Local Version Control

Centralised Version Control

Distributed Version Control

Git Overview

Getting a Remote Repository

git clone https://github.com/{YOUR USERNAME}/git_training.git
  • creates a new directory called git_training on your machine

Cloning a repository

Adding new things

  • Move to the repo directory and add a new file
cd git_training
echo "This is Bob" > Bob.txt
  • Check the status of your working directory and view changes
git status
git diff

Adding Changes

Adding Changes

  • Add changes to the staging area
git add Bob.txt
git diff --staged
  • Commit changes to the local repo
git commit -m "Added Bob"
  • Push changes to the remote
git push

Commit Messages: Bad

Commit Messages: Good

$ git log --oneline -5 --author pwebb --before "Sat Aug 30 2014"
5ba3db6 Fix failing CompositePropertySourceTests
84564a0 Rework @PropertySource early parsing logic
e142fd1 Add tests for ImportSelector meta-data
887815f Update docbook dependency and generate epub
ac8326d Polish mockito usage

Branching

Branching

branching

Branching

  • Create a new branch called updateAlice
git branch updateAlice
  • Switch to the branch we just created
git checkout updateAlice
  • Switch back to master
git checkout master
git branch

Branching

  • Undo and use a shortcut instead
  • Delete branch updateAlice
git branch -d updateAlice
  • Create and update branch in one go
git checkout -b updateAlice
git branch

Creating a branch

Checking out a branch

Making Changes on a Branch

  • Make a change to Alice.txt by adding more text
echo "More content added" >> Alice.txt
  • Add and commit this change
git add Alice.txt
git commit -m "Updated Alice"
  • Push these changes to the remote repository
git push
fatal: The current branch updateAlice has no upstream branch.
To push the current branch and set the remote as upstream, use

    git push --set-upstream origin updateAlice
  • List remote branches
git branch -a

Merging

Merging

Fast-Forward Merge

  • When no new commits have been added to the base branch

3 Way Merge

  • When new commits have been added to the base branch

Fast Forward Merge: Before

merging

Fast Forward Merge: After

merging

Fast Forward Merge

  • See the Updated Alice in commit history on updateAlice branch
git log
  • Checkout master, notice that commit isn't on the master branch
git checkout master
git log
  • Merge the updateAlice branch into master
git merge updateAlice
git log

3 Way Merge: Before

merging

3 Way Merge: After

merging

3 Way Merge

  • Create new branch
git branch newAlice
  • Make changes on master
echo "Some more stuff" >> Bob.txt
git add Bob.txt
git commit -m "Updated Bob"
  • Checkout newAlice branch and make changes there
git checkout newAlice
echo "Even more stuff" >> Alice.txt
git add Alice.txt
git commit -m "Updated Alice again"

3 Way Merge

  • master and updateAlice have now diverged

  • Switch back to master and merge newAlice

git checkout master
git merge newAlice
  • Notice new merge commit Merge branch newAlice
git log --pretty=short
commit 5296df5d5e21747385eed68b1195b05dfce99cfc (HEAD -> master)
Merge: 0c34535 e849430
Author: John French <[email protected]>

    Merge branch 'newAlice'

Merge Conflicts

  • Create and checkout a new branch and make some changes on it
git checkout -b fixBob
echo "Hi! I'm Bob. I've been here for a while now." > Bob.txt
git add Bob.txt
git commit -m "Bob's here for a while"
  • Checkout master and make changes to the same file
git checkout master
echo "Hi! I'm new here." > Bob.txt
git add Bob.txt
git commit -m "Bob's new here"

Merge Conflicts

  • Merging fixBob won't work, files have conflicting changes
git merge fixBob
Auto-merging Bob.txt
CONFLICT (content): Merge conflict in Bob.txt
Automatic merge failed; fix conflicts and then commit the result.
  • View contents of Bob.txt
cat Bob.txt
<<<<<<< HEAD
Hi! I'm new here.
=======
Hi! I'm Bob. I've been here for a while now.
>>>>>>> fixBob

Merge Conflicts

  • Open file in text editor and fix conflict manually (or using a tool)
  • Add and commit fixed file
git add Bob.txt
git commit
  • Too messy! Cancel the merge
git merge --abort

Getting Remote Changes

Keeping your copy of the repository up-to-date

Fetch

Pull

Stashing

  • Save work in progress that's not ready to commit
git stash
  • List stashes
git stash list
  • View a stash
git stash show
  • Apply a stash (retrieve the changes)
git stash apply

Aliases

Creating Command Shortcuts

  • Git aliases are command Shortcuts
    • use sparingly or you'll forget the real syntax
$ git config --global alias.co checkout
$ git config --global alias.ci commit
  • Useful for longer commands

Useful Git Commands

  • Keep notes of new commands you learn
  • Build up a library of handy commands

My Command Library

Action Git Syntax
List tags and commit ids git show-ref --tags
Squash last 4 commits into one commit with new message git reset --soft HEAD~4
Amend last commit message git commit —amend
Force push to remote (overwrites history, Don't do this!) git push -f origin
List tags git tag -l
Check out tag git checkout tags/<TAG>
Show history in format [short SHA1] [message] git log --oneline
Show sha1, author and message of a single commit git log --pretty=short -n 1 <SHA1>
Check if object is present in repo and return its type git cat-file -t [SHA1]
Get last common ancestor of two branches git merge-base branch1 branch2
Abort a merge git merge --abort
Create a new branch and check it out git checkout -b branch_name
List remotes git remote -v
Show details of remote git remote show remote_name
Delete branch from remote git push origin :branch_name
Resolve all conflicting files below a directory with the remote side of the merge (use ours for the local side) `grep -lr '<<<<' .
Resolve conflics in specific file/directory git mergetool <file/directory>
Reset resolved merge conflict to conflicted state git checkout -m <file>
Remove local branches no longer present on remote git remote prune origin
Reset local repo to nth commit behind current HEAD git reset --hard HEAD~n
Revert commit without committing git revert -n <sha1>
Stage changes interactively git add -p
Checkout previously checked-out branch git checkout -
Search in git command history CTRL-R
Check out file from another branch git checkout <branch_name> -- <paths>
Cherry pick a merge commit, appending a line saying “cherry picked from commit” git cherry-pick -x -m 1 <sha1>
Merge a file from another branch git checkout solution; git checkout master README.md; git add README.md; commit -m "Merged README from master"
Create and apply a binary patch git diff-index 79fd4d7 --binary > ~/Desktop/my-patch, Where 79fd4d7 is a placeholder for the commit that came right before the range of commits you want to diff.

So you have a mess on your hands