Installing Git and Upgrading

There are human-friendly Git installers available for Windows and OS X. The installer will generally attempt to keep your settings in place when you upgrade Git.

These installers are available from:

http://git-scm.com/downloads

If you are on Linux or Unix, you probably already have Git installed, but you should upgrade to the latest version. Use your package manager to do this (tips in “Upgrading on *nix Systems”). OS X users may also want to use a package manager to install Git and keep it up to date.

Finding the Command Line

This book is focused on using Git from the command line. I make no apologies about this. There are two critical reasons I think you should give it a try:

1. It’s easier to copy and paste documentation that works on all operating systems when everyone is working from the command line.

2. You get better error messages when you’re working from the command line. In a graphical interface it’s harder to copy and paste the sequence of commands you ran right before getting into the pickle you’re now in. By working from the command line, you will be able to get help faster from others when things go wrong.

As you gain comfort with the concepts in this book, I encourage you to transfer that knowledge to graphical interfaces if you prefer.

Upgrading on *nix Systems

Package managers are a great way to ensure you are using an up-to-date version of Git on your system. On Linux and Unix-variants, you will upgrade Git using the same package manager that you used to install Git previously (well, Git was probably already installed, and you might have needed to upgrade).

When working with a package manager, you need to remember to keep your list of packages up to date. Generally this is with the subcommand update for your package manager. For example, on Ubuntu I would use apt-get update, on Fedora I would use yum check-update, and on OS X, I would use brew update.

Once the list of packages is up to date, you can install the latest packaged version of the software for your system. This is typically done with the subcommand install or upgrade.

OS X:

$ brew install git

Ubuntu, and Linux distributions using the package manager apt:

$ apt-get install git

Fedora, and Linux distributions using the package manager yum:

$ yum install git

To ensure your packages are kept up to date, you can upgrade them individually or on demand (Example B-1). This is typically done with the subcommand upgrade, although running the install command again will generally also work to upgrade the software if a newer package is available.

$ brew upgrade git

$ brew upgrade

OS X Gotchas

When I started getting more involved in the Git community, I began working with custom builds instead of using installers so that I could test out neat new features and upgraded documentation. When I tried to push code to remote repositories, I sometimes ran into the following error:

git: 'credential-osxkeychain' is not a git command. See 'git --help'.

For some reason, my environment variable for $PATH wasn’t behaving quite the way I anticipated. After getting tired of trying to sort it out, I downloaded another copy of the keychain helper and put it in a known location on my hard drive.

First, verify that you have the correct authentication tool set up in your global Git configuration file. This file is located at ~/.gitconfig and should contain the following settings:

[credential]
        helper = osxkeychain
        useHttpPath = true

If this is not visible in the configuration file, set it up now by running the following command:

$ git config --global credential.helper osxkeychain

Check to see if this solved the problem by running the following command:

$ git credential-osxkeychain

You should not receive the error message you had been receiving previously.

If you do receive the error message again, proceed with the following instructions. You will download and “install” a copy of the helper application osxkeychain:

$ curl -s -O http://github-media-downloads.s3.amazonaws.com/
	osx/git-credential-osxkeychain

Adjust the permissions so that you are able to run the program:

$ chmod u+x git-credential-osxkeychain

Move the helper program to the application folder for Unix-y programs. This program is run as root, so you will need to enter your OS X login password to run the command:

$ sudo mv git-credential-osxkeychain /usr/local/git/bin

Now when you run the following command, you shouldn’t get the error you received previously about a missing command:

$ git credential-osxkeychain

This documentation is adapted from the instructions at “Beginner’s Setup Guide for Git & Github on Mac OS X”. Chris Chernoff, if you ever read this, thank you! Your tips saved me from having to enter the 42-character random password I’d set up each time I wanted to push updated branches for this book to the Atlas build server while running custom builds of Git.

Accessing Git Help at the Command Line

Git includes built-in documentation from the command line. This information is accessible by running the following command:

$ git help

You can read all of the available documentation for a given topic by specifying the topic name:

$ git help topic

To navigate the help page, you can can use your keyboard’s arrow keys to scroll up and down. When you are finished reading the documentation page, press q to exit.

For a list of all topics, use the following command:

$ git help --all

A handy glossary of Git terms is also available:

$ git help glossary