1. Basics of GIT for developers and system administrators
GIT Control
Basics of GIT for developers and system administrators
Jennifer Watson
System Engineer
University of Maine System
NECWIC 2017

2. Reasons to USE GIT Working on complex code project
Working on code from more than one computer
Collaborating with others on code or text file
Maintain version control on code or file
Be able to see when code or configuration files have changed and be able to note/read why it was changed
Want to compare or merge different versions
Be able to roll back quickly to last known working version after changes break something
Distributed copies of code or file provide back up in case of lose

3. Installing GIT
Installed by default on modern *nix Operating systems, but may still want to grab latest version
May also consider GUI client
SourceTree (free, Mac and Win)

4. Configuring GIT From a command line:
git config –global user.name “FirstName LastName”
git config –global user.
git config –global color.ui “auto”
Mac/linux
git config – global core.editor “nano –w”
Windows
git config –global core.editor “’c:/program files (x86)/Notepad++/notepad++.exe’ –multiInst –notabbar –nosession noPlugin”
git config --list

5. Create a GIT Repository
From the command line, Make and/or navigate to the directory/folder for Git to track
Type the command:
git init

6. GIT COMMANDS git status git add <file> git commit –m “message”
git log --graph
git diff
git diff –staged
git diff HEAD~1 (can substitute 3 version back you want to compare to current version)
git diff CommitIHash

7. GIT commands (continued)
git checkout <branch>
switch branches
git checkout HEAD~1
Reverts to previously committed version
can be used to undelete a file
git reset HEAD <file>
Un-stage file
git reset --hard
Everything reverted to last commit !
Be careful with reset commands

8. aka Staging
Notice the difference between pull and fetch

9. Working with remote repositories
git clone <url>
git remote add <remote> <url for repository on gitLab or ssh link>
git remote –v
Lists existing remotes
git fetch <remote> <branch> Recommend using fetch instead of pull
git push <remote> <branch>

10. Using REMOTES with ssh cd ~/.ssh ssh-keygen
Open the rsa.pub file created and copy the contents to your remote repository
Begins with ssh-rsa and ends with

11. Typical Day with Git Really Good Day
git fetch <remote> <feature branch>
Or git pull
Work on code
git status
git add <file(s) I worked on/edited>
git commit –m “<message about what I fixed with maybe a tag for ticket closure or release>”
merge/Resolve differences
git push <remote> <feature branch>
Submit a Pull Request for approval
Not so Good Day
git fetch <remote> <feature branch>
Work on code
Get stuck 
git status
git add <file(s) I worked on/edited>
git checkout –b <remote> <nameForNewBranch>
git commit –m “[WIP]<what I was trying to fix and my attempted approach>”
Pull Request (aka Merge Request) to teammate
Receive feedback/help/resolution --> unstuck 
Continue on with Really Good Day workflow

12. Working with a Team in GIT vs Alone
Make sure editor/IDE configured for team agreed upon line lengths
Commit often, but generally push working code that fixes an issue or completes feature
Make sure to fetch prior to push to then merge in any changes that have occurred on the remote
Pull requests allow you to ask someone to review your code for approval, but don’t forget it can also be helpful for asking for help if you get stuck
More prescribed branching
ALONE
Commit often and feel free to push every time as it creates a backup of your code
Only need to fetch and merge changes if you had pushed work from another computer to the remote
This is when to try out and learn about rebasing (only on private branches) !
Do NOT rebase on public branch

13. Git Branching
Source:

14. GIT TIPS Create .gitignore file in at root of git respository
List files to ignore
Can use *.file-extension
can still force add exceptions using git add – f file
Great for excluding files your IDE may add to your Git tracked folder on your local computer
Create hidden file in new folders you create with the following command:
touch .gitkeep
git cannot track an empty folder, so this is basically a placeholder file

15. Git for system administrators
git init on the folders with important configurations
Know if someone else changed them by using git status
And what they changed with git log and git diff
Explain why you changed them with git commit –m “<reason>” so other admins will know
Quickly bring back an earlier working version of the file with git checkout -- <file>
Back up those key configurations easily by git push <remote> <branch>
Note: git keeps track of changes NOT multiple copies of the file, so it does not take up a lot of space

16. Learning resources
Code Academy
More on How to Use in a Team team-environment/