Aston J

Intro to Git – 5 mins to see why it’s awesome

Posted on: June 9th, 2012 by AstonJ No Comments

This is more a handy reference for myself, but it also acts as a very quick intro to why git is awesome and well worth using. The main difference here is I remind you what the state of your working directory is as you make changes (as this was what confused me previously – as I wasn’t quite sure what was going on). I assume you’ve installed git already – and know what it is.

Although we’ll create a demo Rails app, this applies to any app/directory.

Git Basics

Rails new gitdemo
cd git demo
# Create app and cd into the directory

git init
# Starts git repository

git add .
# Adds all files

git status
# Shows status

git commit -m "Initial commit"
# Commits what you've done. -m specifies you want to add a message, which is put in "".

git log
# Shows a log of what you've done

Working with branches/versions

git checkout -b trying-something-out
# Creates a new branch called trying-something-out
# Branches are great because they let you work on forks, and make it easy to undo changes

# For example

rm -rf app/
# That will delete the 'app' directory
## State of your actual directory - the 'app' folder is not there

git status
# Shows you what you've done

git checkout -f
# restores you back to the previous state (keeps you in current branch tho)
## State of your actual directory - the 'app' folder is now back

To get rid of a branch altogether

rm -rf app/
git commit -am "Some changes made"
# commits with flag '-am' which means commit all with a message
## State of your actual directory - the 'app' folder is not there

# Here's how to get it back:

git checkout master
# Switches you back to the master branch
## State of your actual directory - the 'app' folder is back!

git branch
# Shows you which branch you are on

git branch -D trying-something-out
# Deletes branch

To apply changes to the master branch

git checkout -b removing-tmp
rm -rf tmp/
# We create a branch and then delete the tmp directory
## State of your actual directory - the 'tmp' folder is not there

git checkout master
# Takes you back to master
## State of your actual directory - the 'tmp' folder is still not there

git merge removing-tmp
# Applies changes to the master branch
## State of your actual directory - the 'tmp' folder is still not there

git branch -d removing-tmp
# Notice the small 'd' - will only delete after a successful merge

Just note that changes are not saved to your repo until you add them (such as with git add .) and then commit them.

I’ve had all this in my notes for a while – I can’t remember where they came from now but think it was TheRailsTutorial.com :-)

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