Git in gear: How to track changes, travel back in time,

and code nicely with others.

Fureigh @fureigh — info@fureigh.com

NYC Camp April 10, 2014

Who am I?

Fureigh Drupal and CiviCRM developer 2014 Code for America Fellow

info@fureigh.com — fureigh on drupal.org, IRC, Twitter, etc.

Who am I?

What are we going to discuss?

• What version control is and why we care

• Setting up and getting started with Git

• Fundamental commands • How to use Git to experiment safely • How to see who did what when • Simple daily workflow (public repos)

What are we going to discuss?

• GitHub (github.com) – http://try.github.io • This is by no means an exhaustive

guide to Git. See “Resources.” • This will be less fun without a

computer, but you can still learn!

What we’re not doing

What is version control?

(save points for your work.) !

(not only for code.)

Why use version control?(tl;dr: to reduce suffering.)

Why Git in particular?

• Cheap local branching • Multiple workflows • Fast

Let’s try it out!

• Linux: Search for ‘git’ or ‘git-core’sudo yum install git / sudo apt-get install git-core

• Mac:Download from git-scm.com Applications -> Utilities -> Terminal

• Windows:Download from git-scm.com Start -> Programs -> Git -> Git Bash

Installing Git

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Introduce yourself to Git

• Tell it your name: git config --global user.name “Your Name”

• And your email address: git config --global user.email

“your@email.com”

• And avoid unnecessary hassle: git config --global core.safecrlf true

• Make a new project directory: ! mkdir myproject cd myproject

• Tell Git to start paying attention to your project:! git init!

• Check what you’ve done. git status

Starting a new project

• Make a new file: touch newfile.txt

• Add it: git add newfile.txt

• And make an initial commit:! git commit -m “Initial commit.”

• See what you’ve done: git log

Adding and committing

• The smaller your commits, the easier it’ll be for you to go back and see what you’ve done.

• …or undo changes that caused damage.

Commit early and often!

• To edit your last commit message (for the perfectionists among us): git commit --amend -m “You see, what I really meant to say was this.”

Fear of (mis)commitment

• Make a change to newfile.txt. vi newfile.txt

• See which files have been changed: git status

• See more precisely what’s changed: git diff (specific file, patch creation)

Checking what’s different

• It’s also what we use to make patches!

• Make another change: vi newfile.txt

• See what’s changed: git diff

• Make it into a patch: git diff newfile.txt > made- everything-more-awesome.patch

Hey, speaking of diff…

• Your .gitignore file keeps Git from getting cluttered.

• Create it in the root directory of your Git repository.

Keep the crud out

• Let’s make a .gitignore file. touch secret_passwords.txt vi .gitignore .secret_passwords.txt

(Note: case-sensitive!) • What else might we .gitignore? sites/default/settings.php *.DS_Store

• git add .gitignore

moar .gitignore

• Make a new branch and switch to it: git checkout -b 41014-snazzytheme

• View current branches: git branch (Asterisk tells you where you are.)

• (If you wanted to switch back to master:) git checkout master

Using Git to experiment safely

• Make edits. • Check status. • Diff to check what’s changed. • Add files if necessary. • Commit changes. They’ll go to the 41014-snazzytheme branch, NOT to master.

Wash, rinse, repeat.

• First, switch back to master: git checkout master

• You can verify that: git branch

• Merge the other branch: git merge snazzytheme (No squashing!)

• You can see the commit in the log: git log -1 (git log -s)

Putting it back on master

• Delete the ‘snazzytheme’ branch: git branch -d snazzytheme

• You can verify that: git branch

Deleting branches

• If you want to mark a commit as special: git tag -a v1.0 -m “Initial launch!”

• Tell me all about that, Git. git show v1.0

Tagging

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But wait! Something’s gone wrong!

!(let’s say)

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photo by Amy Strycula (http://www.amystrycula.com) (Amy Strycula's personal archive) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

• Say you delete a file: git rm newfile.txt

• J/k! Forget everything since my last commit! git reset --hard

• Check that all’s well: git status

• For individual files: git checkout yesterday.txt

Turning back (recent) time

• What happened? When do you hypothesize was last-known-good? git log git blame – who did this?

• First 5 characters of each long string are a commit ID.

• To view changes between second and third commits: git diff 22222:33333

• To revert: git revert HEAD <- reverts most recent or: git checkout 22222 filename.txt

Disaster recovery

• (git clone)

• git checkout master

• git pull

• git checkout -b issue-branch Creates and switches you into a branch.

• git status (as you’re going along)

• git add [filename]

• git diff

• git commit -m “Detailed commit message.”

• git checkout master

• git merge issue-branch

• git push; git branch -d issue-branch

Simple daily workflow

http://nakedstartup.com/2010/04/simple-daily-git-workflow/

• Each project (module, theme, etc.) gets its own repository.

• Who gets commit access? Project administrator and people to whom they grant permission.

• If you’re a project creator, follow the steps on the Version Control tab of your project’s page.

• That page also lets anyone clone the git repo. Perfect for making patches.

• drupal.org/documentation/git

Git on drupal.org

• git log —name-only

• git add -p !

• git merge --squash

• (fun with git config: color diffing and more)

Gittin’ fancy

• git-scm.com • Drupal-specific: drupal.org/documentation/

git Includes GUI recommendations.

• gitready.com – great for quick answers • gitimmersion.com – beautiful • openhatch.org/missions/git – practice! • try.github.com

Resources

• nyccamp.org/sprint-mentor-sign-up

Thanks! Now come help at Sunday’s sprint!

Fureigh fureigh.com

info@fureigh.com @fureigh

Thanks!