Git Basics

In this technical post we will cover the basic and essential commands in Git. Thank you Linus Torvalds for your creations and for making this developer world a best place to live.

The getting started recipe

echo "# git-workshop" >> README.md
git init
git add README.md
git commit -m "first commit"
git remote add origin git@github.com:josdem/git-workshop.git
git push -u origin master

Where:

  • git init Create a new git repository
  • git add Add a new file
  • git commit -m Commit changes from a single file
  • git remote add Add a new remote repository
  • git push Push your commits to remote repository

Branching

In order to develop features isolated from each other we can use branches, repositories consists of “trees” maintained by git. So you have master as main tree and you will be able to create as many branches as you want. Use branches for development and merge them back to the master upon completion.

git checkout -b feature/1

With previous command we created a new feature branch, usually we create a branch for each new feature we are working. So let’s create a new file called Chapter_1.md.

# Chapter 1

When I was six years old, I saw, once, a splendid picture.

Then let’s add that file to our local repository

git add Chapter_1.md
gc -m "#1 Adding Chapter 1 file"

Now let’s add more content to our file

# Chapter 1

When I was six years old, I saw, once, a splendid picture, in a book about the virgin forest called *Stories of Life*. It represented a boa snake that swallowed a wildcat. This is the copy of the drawing.

![Snake Swallowed a Wildcat](/img/snake_swallowed_wildcat.png)

And then other commit

git commit -m "#1 Completing first paragraph"

Here we are adding “#1 …” as feature reference. You can continue adding and committing changes with descriptive comments, try to do small changes for each commit so in that way will be easier to do code reviews. Once you complete your feature you can merge that changes to master.

git checkout master
git merge feature/1
git push origin master

Checkout

You can create a fresh copy of a local repository by running this command

git clone git@github.com:josdem/git-workshop.git

At this point you have only master, you can see that with this command:

git branch

Output

* master
(END)

In order to update remote tracking branches you can use this command

git fetch

Then you can use this command to move to the fresh copy of feature/1 branch

git checkout feature/1

Output

Branch 'feature/1' set up to track remote branch 'feature/1' from 'origin'.
Switched to a new branch 'feature/1'

Now we should have two local branches ready

git branch

Output

* feature/1
  master
(END)

Delete a branch

You can delete a local branch with this command

git branch -d feature/1

If you want to delete a remote branch you can use this command

git push origin --delete feature/1

Pull

To incorporate changes from a remote repository into the local branch use this command

git pull origin branch_name

That’s it git pull, updates your current local branch with the latest changes from the remote server. git fetch never change or update any of your own local branches, it a is safe operation.

Status

Git status command displays the state of the working directory.

git status

It lets you see which changes have been staged, which haven’t, and which files aren’t being tracked by Git.

Ignore

Ignored files are usually build directories and generated files. It is a good practice to ignore those files, you simply need to create a file named .gitignore and add path plus file names.

credentials.yml
.classpath
build/
*.log
**swp

For example:

  • credentials.yml Is a personal file with your username and password
  • .classpath A computer generated file
  • build/ A computer generated directory
  • *.log An asterisk is a wildcard that matches zero or more characters
  • **swp Double asterisk to match directories anywhere in the repository

Log

The simpliest way to see your repository history is using this command:

git log

Output

commit 57b3fcd5985d5a905690154ff37d83753b2a0fcc
Author: josdem <joseluis.delacruz@gmail.com>
Date:   Sat Feb 23 09:24:32 2019 -0500

    #1 Adding image

commit fc5266ceb809a161d82db3b54c906efac846c1e3
Author: josdem <joseluis.delacruz@gmail.com>
Date:   Sat Feb 23 09:10:43 2019 -0500

    #1 Changing file name

commit 33d8a5feb6329c87f525685b39ce5e9b076cd3f3
Author: josdem <joseluis.delacruz@gmail.com>
Date:   Sat Feb 23 09:07:58 2019 -0500

    #1 Deleting Chapter 1 in txt format

commit 89365cd47aee0a534f2bb65fd1ebbd1600f6d0e3
Author: josdem <joseluis.delacruz@gmail.com>

To see only the commits of a certain author

git log --author=josdem

Compressed log where each commit has a single line

git log --pretty=oneline

Output

57b3fcd5985d5a905690154ff37d83753b2a0fcc #1 Adding image
fc5266ceb809a161d82db3b54c906efac846c1e3 #1 Changing file name
33d8a5feb6329c87f525685b39ce5e9b076cd3f3 #1 Deleting Chapter 1 in txt format
89365cd47aee0a534f2bb65fd1ebbd1600f6d0e3 #1 Adding Chapter 1 file
3929d19b3183f36a2c22350b621267142d0f713d #1 Adding first line in Chapter 1
b2fefdbc93de041541b2c1cda0da26e8369a9cd8 #1 Adding Chapter 1
306b0c78b8062ed59c81d3262916d827f61a64f7 Adding Git ignore file
52d856f9c2b44352abd77487891cdfba4af0f3b9 first commit

Undo

In case you did something wrong, you can replace local changes using this command

git checkout -- filename

For a single file or

git checkout .

To undo all changes. For a complete Git reference go here. To browse the project go here, to download the project:

git clone git@github.com:josdem/git-workshop.git

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