Creating a Repository

Overview

Teaching: 10 min
Exercises: 0 min

Questions

• Where does Git store information?

Objectives

• Create a local Git repository.

Once Git is configured, we can start using it. Let’s create a directory for our work and then move into that directory:

$ mkdir planets
$ cd planets

Then we tell Git to make planets a repository—a place where Git can store versions of our files:

$ git init

If we use ls to show the directory’s contents, it appears that nothing has changed:

$ ls

But if we add the -a flag to show everything, we can see that Git has created a hidden directory within planets called .git:

$ ls -a

.	..	.git

Git stores information about the project in this special sub-directory. If we ever delete it, we will lose the project’s history.

We can check that everything is set up correctly by asking Git to tell us the status of our project:

$ git status

# On branch master
#
# Initial commit
#
nothing to commit (create/copy files and use "git add" to track)

Places to Create Git Repositories

Dracula starts a new project, moons, related to his planets project. Despite Wolfman’s concerns, he enters the following sequence of commands to create one Git repository inside another:

$ cd             # return to home directory
$ mkdir planets  # make a new directory planets
$ cd planets     # go into planets
$ git init       # make the planets directory a Git repository
$ mkdir moons    # make a sub-directory planets/moons
$ cd moons       # go into planets/moons
$ git init       # make the moons sub-directory a Git repository

Why is it a bad idea to do this? (Notice here that the planets project is now also tracking the entire moons repository.) How can Dracula undo his last git init?

Solution

Git repositories can interfere with each other if they are “nested” in the directory of another: the outer repository will try to version-control the inner repository. Therefore, it’s best to create each new Git repository in a separate directory. To be sure that there is no conflicting repository in the directory, check the output of git status. If it looks like the following, you are good to go to create a new repository as shown above:

$ git status

fatal: Not a git repository (or any of the parent directories): .git

Note that we can track files in directories within a Git:

$ touch moon phobos deimos titan    # create moon files
$ cd ..                             # return to planets directory
$ ls moons                          # list contents of the moons directory
$ git add moons/*                   # add all contents of planets/moons
$ git status                        # show moons files in staging area
$ git commit -m "add moon files"    # commit planets/moons to planets Git repository

Similarly, we can ignore (as discussed later) entire directories, such as the moons directory:

$ nano .gitignore # open the .gitignore file in the texteditor to add the moons directory
$ cat .gitignore # if you run cat afterwards, it should look like this:

moons

To recover from this little mistake, Dracula can just remove the .git folder in the moons subdirectory. To do so he can run the following command from inside the ‘moons’ directory:

$ rm -rf moons/.git

But be careful! Running this command in the wrong directory, will remove the entire git-history of a project you might wanted to keep. Therefore, always check your current directory using the command pwd.

Key Points

• git init initializes a repository.