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This lesson is a subset of one of Debug Academy's git lessons.
Git is a Version Control System, or 'VCS'. It takes snapshots of the state of files when changes are made. It is extremely beneficial and necessary on any large software project. It is a red flag if a software development company is not enforcing the use of version control.
A practice assignment can be found in the repository under the name: git_assignment.md
Use the Git OS X Installer ( http://code.google.com/p/git-osx-installer/ ). If you use the Homebrew package manager, run brew install git. You might want to install GitX (GUI).
Use Git for Windows ( http://msysgit.github.io/ ) (command line).
Use the command sudo apt-get install git-core to install Git using the command line.
Follow the installation options that will be presented to you.
Git keeps track of the history of files changed - including who made each change. Because of which, you are required to configure your name and e-mail address.
To configure your name and e-mail address, enter the following 2 commands into the command line where you will be using git:
git config --global user.name "YOUR NAME"
git config --global user.email "YOUR EMAIL ADDRESS"
If you are new to programming, you likely spend most of your computer-time using a GUI (pronounced gooey). A GUI is a user interface designed to hide the complexity behind applications. We will be using the terminal for portions of this Git lesson.
Below you will find a subset of Debug Academy's command line basics lesson.
- ls => 'list'
- Lists files and folders in the current directory
- 'cd' = >'Change Directory'
- Used for navigating to other folders
- Can use an absolute (entire) path: cd /Users/ashraf/Desktop/debugsociety/subfolder-name
- Absolute paths begin with a /
- Can use a relative path:
- cd /Users/ashraf/Desktop
- Used an absolute path to get to the Desktop folder
- cd debugsociety
- Because the debugsociety folder is within my current folder, I can use a relative path.
- cd subfolder-name
- Because subfolder-name is in my current folder, I can use a relative path.
- Asterisks means 'anything'.
- In many commands, can be used as part of a filename to expand the command. For example:
- Can be used to select all files in a folder
- mv files/* files/ashraf/
- Can be used to move files based on a partial filename
- mv files/*.pdf files/ashraf/
- This moved everything in the 'files' folder whose name ends in '.pdf'.
- mv files/a* files/ashraf/
- This moved everything in the 'files' folder whose name starts with 'a'.
- mv files/tmp files/trash
- This moved everything in the 'files' folder whose name contains 'tmp'.
- Used to denote 'up one level'
- To change to the directory 'up one level': cd ../
- Can be combined to go up multiple levels:
- cd ../../
- That takes you up two levels
- Used to denote 'current directory'
- Example: mv files/file1.html ./
- We moved a file from the 'files' folder into the folder we are currently in.
Below is a subset of the Debug Academy lesson on git commands. It covers the commands we will be using throughout this assignment.
- For creating a new git repository.
- It turns the current directory into a git repository.
- For example:
- 'cd' into a non-git folder.
- Type 'git init'.
- Now the folder is a git repository.
- For copying (aka cloning) a repo (and all files in it) from a URL to your computer.
- For example:
- "git clone https://github.com/debugacademy/debugacademy-git.git da-git"
- That will download a copy of the entire debugacademy-git repository into a local folder (on your computer) called 'da-git'
- Includes the 'add'ed files in your next commit.
- Changes to files that were not 'add'ed will remain untracked by git.
- Filenames must be typed exactly and with extensions.
- For example, if you want to add a file named File1.html to your next commit:
- git add File1.html will work.
- 'git add File1' will NOT work.
- 'git add file1.html' will NOT work.
- Stores the current version of all files that were added using 'git add'.
- There should be a commit for every meaningful change.
- There should be a short message describing what the commit is for.
- For example: git commit -m "Updated git_commands.md"
- If this message displayed: no changes added to commit, it means you did not 'git add' your changes before committing them.
- Used to switch branches.
- For example:
- I am on the 'master' branch
- git checkout hello-world
- If it exists, I am taken to the branch named 'hello-world'
- For example:
- Used to create a new branch named [new-branch], which initially matches the branch named [branch] exactly
- For example:
- git checkout -b my-branch master
- The branch 'my-branch' is created based off of the 'master' branch
- Then I am taken to the new 'my-branch' branch
- For example:
- Adds a remote connection to a repository.
- For example:
- git remote add ds https://github.com/debugacademy/debugacademy-git.git
- Now we are connected to (can pull from) the 'debugacademy/debugacademy-git' repo.
- If we have the right privileges, we can also now push to the 'debugacademy/debugacademy-git' repo.
- i.e. git pull ds master ## this command will now automatically pull from debugacademy/debugacademy-git.git
- Shows the nicknames of the remote repositories that your repo is connected to.
- For example:
- git remote might display:
- origin
- ds
- Passing the -v flag shows more detail.
- For example:
- git remote -v might display:
- Shows you the branches on your computer
- Places an asterisk next to the branch you are on.
- Used for sending commits from [branch] to [remote]/[same branch]
- Sends ALL committed work on [branch you are pushing]
- Immediately/automatically merges all new changes from [remote]/[branch name] to the branch you currently have checked out.
- When you git pull, make sure you have the branch you want to pull into checked out
- For example, if I want to pull from debugacademy's 'master' branch into my 'branch2' branch
- git checkout branch2
- git pull debugacademy master
- Merges work from [branch name] into the branch you currently have checked out.
- For example, if I have branch2 and branch4 in my local repository and I want to bring the changes from branch4 into branch2
- git checkout branch2
- git merge branch4
- If it says 'merge conflict', that means the two branches make changes to the same section of the same file
- Git will insert the changes from BOTH branches in the file
- Git will insert '<<<' within the file(s), before each conflict
- Git will insert '>>>' within the file(s), after each conflict
- It is your job to review what git has added to the files, then to remove what you do not want. Such as '<<<' and '>>>'.
- After resolving the conflict, it is your job to add and commit your changes.
- Following git workflows such as 'git flow' minimize messy merge conflicts.
Sometimes, especially after a git merge or git commit, people find themselves seeing a bunch of text but being unable to type. If this happened to you, you likely are seeing the text editor 'vim'.
vim is a popular, advanced command line editor.
- To enable typing, press
ifor 'Insert' - To save the file, press 'escape', then
:, thenw(for write), thenENTER - To exit a file and leave vim, press 'escape', then
:, thenq(for quit), thenENTER- You may need to press
yif you have unsaved changed
- You may need to press