Overview

Teaching: 5 min
Exercises: 0 min

Questions

• How do I get set up to use Git?

Objectives

• Configure git the first time it is used on a computer.

• Understand the meaning of the --global configuration flag.

• Set up github.com to use ssh keys

When we use Git on a new computer for the first time, we need to configure a few things. Below are a few examples of configurations we will set as we get started with Git:

• our name and email address,
• what our preferred text editor is,
• and that we want to use these settings globally (i.e. for every project).

On a command line, Git commands are written as git verb options, where verb is what we actually want to do and options is additional optional information which may be needed for the verb. So here is how Dracula sets up his new laptop:

$ git config --global user.name "Vlad Dracula"
$ git config --global user.email "vlad@tran.sylvan.ia"

Please use your own name and email address instead of Dracula’s. This user name and email will be associated with your subsequent Git activity, which means that any changes pushed to GitHub, BitBucket, GitLab or another Git host server in a later lesson will include this information.

Line Endings

As with other keys, when you hit Return on your keyboard, your computer encodes this input as a character. Different operating systems use different character(s) to represent the end of a line. (You may also hear these referred to as newlines or line breaks.) Because Git uses these characters to compare files, it may cause unexpected issues when editing a file on different machines. Though it is beyond the scope of this lesson, you can read more about this issue on this GitHub page.

You can change the way Git recognizes and encodes line endings using the core.autocrlf command to git config. The following settings are recommended:

On macOS and Linux:

$ git config --global core.autocrlf input

And on Windows:

$ git config --global core.autocrlf true

For these lessons, we will be interacting with GitHub and so the email address used should be the same as the one used when setting up your GitHub account. If you are concerned about privacy, please review GitHub’s instructions for keeping your email address private. If you elect to use a private email address with GitHub, then use that same email address for the user.email value, e.g. username@users.noreply.github.com replacing username with your GitHub one. You can change the email address later on by using the git config command again.

Dracula also has to set his favorite text editor, following this table:

It is possible to reconfigure the text editor for Git whenever you want to change it.

Exiting Vim

Note that Vim is the default editor for many programs. If you haven’t used Vim before and wish to exit a session without saving your changes, press Esc then type :q! and hit Return. If you want to save your changes and quit, press Esc then type :wq and hit Return.

The four commands we just ran above only need to be run once: the flag --global tells Git to use the settings for every project, in your user account, on this computer.

You can check your settings at any time:

$ git config --list

You can change your configuration as many times as you want: use the same commands to choose another editor or update your email address.

Proxy

In some networks you need to use a proxy. If this is the case, you may also need to tell Git about the proxy:

$ git config --global http.proxy proxy-url
$ git config --global https.proxy proxy-url

To disable the proxy, use

$ git config --global --unset http.proxy
$ git config --global --unset https.proxy

Git Help and Manual

Always remember that if you forget a git command, you can access the list of commands by using -h and access the Git manual by using --help :

$ git config -h
$ git config --help

Setting up SSH keys

In the lesson today we will use SSH keys for fast easy access to github.com. First we need to generate an SSH key for the machine we’re using, with

$ ssh-keygen

We can press enter to accept the default location. You may choose a passphrase to protect your keys, or you can leave this empty.

Warning: overwriting keys

If you already have a key, ssh-keygen will warn you that it is about to overwrite a file. If this happens, press n and then ENTER to confirm that you don’t want to overwrite the file. You can skip on to the next step.

Next we want to add this key on github.com. To do this, visit the https://github.com/settings/keys page, and hit the “New Key” button. You should see the following menu box:

Enter a meaningful description of the machine your using that will make sense to future you, such as “Work Laptop”. In the Key field, we should enter the public RSA key. We can get this key by typing at the command line

$ cat ~/.ssh/id_rsa.pub

Copy the output of this command into the Key field and hit the “Add SSH Key” button to submit.

You should be able to connect to github.com now. We can verify this with

$ ssh -T git@github.com

You may see one of the following warnings:

The authenticity of host 'github.com (IP ADDRESS)' can't be established.
RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
Are you sure you want to continue connecting (yes/no)?

or

The authenticity of host 'github.com (IP ADDRESS)' can't be established.
RSA key fingerprint is SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8.
Are you sure you want to continue connecting (yes/no)?

Verify that the message you see matches one of the ones above. If it does, continue by typing

yes

and hitting enter. You should then see a message which says

Hi <username>! You've successfully authenticated, but GitHub does not
provide shell access.

The placeholder <username> in this text should contain your github username. If it does, then the setup is correct and we’re good to go! If you get anything else, check your setup or ask a helper to look over your setup with you before proceeding.

Key Points

• Use git config with the --global option to configure a user name, email address, editor, and other preferences once per machine.

• Set up ssh keys to connect to github.com