The Basics

Install Git

Windows Instructions

Git on Windows

Linux Instructions

Git on Linux

Mac Instructions

Git on Mac

If you have homebrew installed

$ brew install git

Configure Git

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

Create Repository From Existing Code

$ cd existing-code-directory
$ git init
$ git add *
$ git commit -m "Initial checkin"

Adding a Remote Server

$ git remote add https://github.com/cruft/my-repo.git

Cloning Existing Repository

$ git clone ssh://[email protected]/your-name-here/your-repo.git
$ git add FileThatChanged.java
$ git commit -m "I implemented blah for flurp"
$ git push origin HEAD

Working With Git

Pulling in Code from Master

$ git pull origin master

Creating Branches

$ git checkout -b branch_name

Switching Branches

$ git checkout master

Checking out Remote Branch

$ git fetch
$ git checkout remote_branch

Merging Branches

$ git merge branch_name

Deleting Local Branch

$ git branch -d <branch-name>
$ git branch -D <brach-name> # - force delete

Deleting Remote Branch

$ git push origin :<branch-name>
$ git push origin --delete <branch-name>

Creating a tag

$ git tag V1.0
$ git tag -a v1.1 -m "Creating version 1.1" # Creates a tag with a message
$ git tag -a v1.2 9fceb02 -m "Creating tag for 1.2 from commit hash"

Showing tags

$ git tag
$ git tag -l "v1.8.5*" # show tags of a particular pattern

Saving Tags

$ git push origin v1.1 # Save tag to remote
$ git push origin --tags # Save all local tags to remote

Deleting Tags

$ git tag -d v1.1 # Delete local tag
$ git push origin --delete v1.1 # Delete remote tag

Checking out Tags

$ git checkout v1.1 # Check out tag in in “detached HEAD” state
$ git checkout -b version2 v2.0.0 # Checkout tag to branch

Pruning local tracking branches

$ git fetch -p <remote-branch> # single branch
$ git fetch -p # Mutiple remote tracking deletes

Getting My Codes Status

$ git status

Staging Changes

$ git add path/to/my/file/SomeFile.java

Unstaging a Staged File

$ git reset HEAD path/to/my/file/SomeFile.java

Unmodifying a Modified File

$ git checkout -- path/to/my/file/SomeFile.java

Committing Code

$ git commit -m "I added code"

Staging and Committing Code

$ git commit -a -m "Commit Message"

Changing Last Commit

This can be used to change a message, add, and/or remove files

$ git commit --amend -m "Change the commit message"
$ git add NewFile.java
$ git commit --amend

Putting Committed Code on Remote Server

$ git push origin HEAD

Pulling Code from Remote Server

$ git pull --rebase

Viewing Difference in Your Code and Repository

$ git diff

Moving or Renaming a File

$ git mv /path/to/my/file/SomeFile.java /new/path/SomeFile.java

View Git History

$ git log
$ git reflog

Removing a file from Git

$ git rm path/to/my/file/SomeFile.java

Removing a file from Git, but keeping it on Disk

$ git rm --cached local.file

Revert Commit

Find the commit you want to revert

$ git log
You should see an output of the repository history
commit 54533995148bc91424b7ca2493230a09f6cb9acb
Author: Homer Simpson <[email protected]>
Date:   Mon Oct 10 14:19:04 2016 -0400


    Added auto cool of tap.


commit 7de86787eabc55799085a7ab7e22cf04c83d31ab
Author: Krusty.Clown <[email protected]>
Date:   Mon Oct 10 14:54:12 2016 -0400


    PUB-1222 - Krusty C, Sideshow B - Added the humor tap squirt feature.

Select the commit hash to revert

$ git revert 54533995148bc91424b7ca2493230a09f6cb9acb

Add your revert message

Creating Aliases

$ vi ~/.gitconfig

Add entries like below

[alias]
st = status
pr = pull --rebase
pm = pull origin master
co = checkout

Common Problem

I assume you have git command line installed by now.

Changing the last commit message

This should only be done prior to pushing to a remote branch. Caveat Emptor

$ git commit --amend -m "STORY-1234 - Updated commit message"

Showing files staged for commit

$ git show --name-only

Undoing a Commit

If you have a commit that you want to undo, there is a simple workaround

$ git reflog
    4c20138 HEAD@{0}: checkout: moving from feature/STORY-1234 to master
    4c20138 HEAD@{1}: checkout: moving from master to feature/STORY-1234
    4c20138 HEAD@{2}: pull origin master: Merge made by the 'recursive' strategy.
    3c3dace HEAD@{3}: commit: STORY-1234 - Bad unit of work
$ git reset --soft HEAD~3

Staging Change Shards

$ git add -p

The output will look something like below:

diff --git a/README.md b/README.md
    index f00c19d..ef40e35 100644
    --- a/README.md
    +++ b/README.md
    @@ -1,7 +1,7 @@
    # Q Platform Vagrant Setup
  
    ## Prerequisites
    -
    +      
    Stage this hunk [y,n,q,a,d,/,j,J,g,e,?]?

Fixing Merge Conflicts

$ git mergetool

Showing the History of a File

$ git log --follow -p -- path/to/file/SomeFile.java

Git Rebase has conflicts

You should resolve the conflicts using your merge tool. After that continue the rebase

$ git rebase --continue

Overwrite Local Files on Pull

This will cause local changes to be lost, Caveat Emptor

$ git fetch --all
$ git reset --hard origin/master

Move untracked changes to a Branch

To see the unstaged file, check the status

$ git status
    On branch master
    Your branch is up-to-date with 'origin/master'.
    Untracked files:
    (use "git add <file>..." to include in what will be committed)


    new_file


    nothing added to commit but untracked files present (use "git add" to track)

This shows that new_file is not tracked

$ git checkout -b new_branch
$ git add new_file
$ git commit -m "Added files to new branch"

Git Ignore

$ git add .gitignore
$ git commit -m "Added git ignore file"
$ git push origin HEAD

Check out the Documentation for information how to set up the file

Git Clone Tag or Branch

$ git clone https://my-git-repo.com/my-app.git -b my-tag-1.0
$ git clone https://my-git-repo.com/my-app.git -b my-branch
$ git clone https://my-git-repo.com/my-app.git --branch my-tag-1.0
$ git clone https://my-git-repo.com/my-app.git --branch my-branch

Remove local untracked files

$ git clean -fd

Undo last local commit

$ git reset --soft HEAD~

Tips and Tricks

Here are some useful tips and tricks for making working with Git easier.

Reuse the Previous Commit Message

$ git commit --reedit-message=HEAD --reset-author

Show the Remote Origin Server

$ git remote show origin

Amend commit with out updating message

$ git commit --amend --no-edit

Stash Changes

$ git stash 

This will take all changed files in local repository and stash them locally in a stash stack

List Stash Changes

$ git stash list 

This will list all of the stashed changes in your stash stack

Show Stashed Changes

$ git stash show -p stash@{1}

This will show all of the changes on that particular stash stack location

Un-Stash Changes

$ git stash pop

This will take stashed files and apply them to your working HEAD. This also removes them from the stash stack.

Apply Stashed Changes

$ git stash apply 

This will take all changed files stashed and apply them to your local HEAD. This leaves the stashed changes on the stash stack

Drop Stashed Changes

$ git stash drop

This will take remove the changes at the top of your stash stack.

Clear Stashed Changes

$ git stash clear

This clear your stash stack.

Rename a Branch

$ git branch -m "new_branch_name" # If you are on the branch locally
$ git branch -m old-name new-name # If you are not on the branch to rename
$ git push origin :old_branch # Delete the old branch
$ git push origin HEAD # Push the renamed branch to origin

DANGER WILL ROBINSON!!

This is when things go awry and you need some help.

Revert a bunch of commits

Say you pushed code to the (master) branch instead of (develop) and you need to revert everything back to the last merge down to master.

$ git log

This will show you the commit history, like so:

commit 6290518ffd80d8dbb393ac144804f1069040f2e7
Merge: f428d60 e39a178
Author: Mickey Mouse  <[email protected]>
Date:   Tue May 2 16:02:16 2017 +0000

    Merge pull request #183 in PRP/de-prp from bugfix/PRP-515-Integration_bug to release/v1.2.0

    * commit 'e39a178c32ff35e41c13437951fbc3a8cfecc9be':
      Fixed integration broken because of prp-515

commit e39a178c32ff35e41c13437951fbc3a8cfecc9be
Author: Donald.Duck <[email protected]>
Date:   Tue May 2 11:45:52 2017 -0400

    Fixed Broken Tests
commit dc71d964818c382b090bc90cb214d0d0b356c743
Merge: c6f68a8 6290518
Author: Mickey Mouse <[email protected]>
Date:   Tue May 2 13:15:07 2017 -0400

    Merge remote-tracking branch 'origin/release/v1.2.0' into master

Find the last good commit hash

$ git reset dc71d964818c382b090bc90cb214d0d0b356c743 --soft

You can do a --hard and it will remove all of the changes that are between where you are and that commit. A --soft will keep those changes as staged in your local.

$ git push --force HEAD

THIS IS A BIG NO NO, usually. Only do this if you are sure that no one is working off of the remote branch.