Git for beginners: The definitive practical guide

Question

Ok, after seeing this post by PJ Hyett, I have decided to skip to the end and go with Git.

So what I need is a beginner's practical guide to Git. "Beginner" being defined as someone who knows how to handle their compiler, understands to some level what a Makefile is, and has touched source control without understanding it very well.

"Practical" being defined as this person doesn't want to get into great detail regarding what Git is doing in the background, and doesn't even care (or know) that it's distributed. Your answers might hint at the possibilities, but try to aim for the beginner that wants to keep a 'main' repository on a 'server' which is backed up and secure, and treat their local repository as merely a 'client' resource.

Procedural note: PLEASE pick one and only one of the below topics and answer it clearly and concisely in any given answer. Don't try to jam a bunch of information into one answer. Don't just link to other resources - cut and paste with attribution if copyright allows, otherwise learn it and explain it in your own words (that is, don't make people leave this page to learn a task). Please comment on, or edit, an already existing answer unless your explanation is very different and you think the community is better served with a different explanation rather than altering the existing explanation.

So:

Installation/Setup

• How to install Git
• How do you set up Git? Try to cover Linux, Windows, Mac, think 'client/server' mindset.
  • Setup GIT Server with Msysgit on Windows
• How do you create a new project/repository?
• How do you configure it to ignore files (.obj, .user, etc) that are not really part of the codebase?

Working with the code

• How do you get the latest code?
• How do you check out code?
• How do you commit changes?
• How do you see what's uncommitted, or the status of your current codebase?
• How do you destroy unwanted commits?
• How do you compare two revisions of a file, or your current file and a previous revision?
• How do you see the history of revisions to a file?
• How do you handle binary files (visio docs, for instance, or compiler environments)?
• How do you merge files changed at the "same time"?
• How do you undo (revert or reset) a commit?

Tagging, branching, releases, baselines

• How do you 'mark' 'tag' or 'release' a particular set of revisions for a particular set of files so you can always pull that one later?
• How do you pull a particular 'release'?
• How do you branch?
• How do you merge branches?
• How do you resolve conflicts and complete the merge?
• How do you merge parts of one branch into another branch?
• What is rebasing?
• How do I track remote branches?
• How can I create a branch on a remote repository?

Other

• Describe and link to a good GUI, IDE plugin, etc. that makes Git a non-command line resource, but please list its limitations as well as its good.
  • msysgit - Cross platform, included with Git
  • gitk - Cross platform history viewer, included with Git
  • gitnub - Mac OS X
  • gitx - Mac OS X history viewer
  • smartgit - Cross platform, commercial, beta
  • tig - console GUI for Linux
  • qgit - GUI for Windows, Linux
  • Git Extensions - package for Windows, includes friendly GUI
• Any other common tasks a beginner should know?
  • Git Status tells you what you just did, what branch you have, and other useful information
• How do I work effectively with a subversion repository set as my source control source?

Other Git beginner's references

• Git guide
• Git book
• Git magic
• gitcasts
• GitHub guides
• Git tutorial
• Progit - book by Scott Chacon
• Git - SVN Crash Course
• Git from the bottom up
• Git ready
• gitref.org

Delving into Git

• Understanding Git conceptually

I will go through the entries from time to time and 'tidy' them up so they have a consistent look/feel and it's easy to scan the list - feel free to follow a simple "header - brief explanation - list of instructions - gotchas and extra info" template. I'll also link to the entries from the bullet list above so it's easy to find them later.

Answer 1

Well, despite the fact that you asked that we not "simply" link to other resources, it's pretty foolish when there already exists a community grown (and growing) resource that's really quite good: the Git Community Book. Seriously, this 20+ questions in a question is going to be anything but concise and consistent. The Git Community Book is available as both HTML and PDF and answers many of your questions with clear, well formatted and peer reviewed answers and in a format that allows you to jump straight to your problem at hand.

Alas, if my post really upsets you then I'll delete it. Just say so.

Answer 2

Why yet another howto? There are really good ones on the net, like the git guide which is perfect to begin. It has good links including the git book to which one can contribute (hosted on git hub) and which is perfect for this collective task.

On stackoverflow, I would really prefer to see your favorite tricks !

Mine, which I discovered only lately, is git stash, explained here, which enables you to save your current job and go to another branch

EDIT: as the previous post, if you really prefer stackoverlow format with posts as a wiki I will delete this answer

Answer 3

Commit Changes

Once you've edited a file, you need to commit your changes to git. When you execute this command it will ask for a commit message - which is just a simple bit of text that tells everyone what you've changed.

$ git commit source/main.c

Will commit the file main.c in the directory ./source/

$ git commit -a # the -a flag pulls in all modified files

will commit all changed files (but not new files, those need to be added to the index with git-add). If you want to commit only certain files then you will need to stage them first with git-add and then commit without the -a flag.

Commiting only changes your local repository though not the remote repositories. If you want to send the commits to the remote repository then you will need to do a push.

$ git push <remote> <branch> # push new commits to the <branch> on the <remote> repository

For someone coming from CVS or SVN this is a change since the commit to the central repository now requires two steps.

Answer 4

Git Magic is all you'll ever need. Guaranteed or your money back!

Answer 5

How to configure it to ignore files:

The ability to have git ignore files you don't wish it to track is very useful.

To ignore a file or set of files you supply a pattern. The pattern syntax for git is fairly simple, but powerful. It is applicable to all three of the different files I will mention bellow.

• A blank line ignores no files, it is generally used as a separator.
• Lines staring with # serve as comments.
• The ! prefix is optional and will negate the pattern. Any negated pattern that matches will override lower precedence patterns.
• Supports advanced expressions and wild cards
  • Ex: The pattern: *.[oa] will ignore all files in the repository ending in .o or .a (object and archive files)
• If a pattern has a directory ending with a slash git will only match this directory and paths underneath it. This excludes regular files and symbolic links from the match.
• A leading slash will match all files in that path name.
  • Ex: The pattern /*.c will match the file foo.c but not bar/awesome.c

Great Example from the gitignore(5) man page:

$ git status
[...]
# Untracked files:
[...]
#       Documentation/foo.html
#       Documentation/gitignore.html
#       file.o
#       lib.a
#       src/internal.o
[...]
$ cat .git/info/exclude
  # ignore objects and archives, anywhere in the tree.
  *.[oa]
$ cat Documentation/.gitignore
# ignore generated html files,
*.html
# except foo.html which is maintained by hand
!foo.html
$ git status
[...]
# Untracked files:
[...]
#       Documentation/foo.html
[...]

---

Generally there are three different ways to ignore untracked files.

1) Ignore for all users of the repository:

Add a file named .gitignore to the root of your working copy.

Edit .gitignore to match your preferences for which files should/shouldn't be ignored.

git add .gitignore

and commit when you're done.

2) Ignore for only your copy of the repository:

Add/Edit the file $GIT_DIR/info/exclude in your working copy, with your preferred patterns.

Ex: My working copy is ~/src/project1 so I would edit ~/src/project1/.git/info/exclude

You're done!

3) Ignore in all situations, on your system:

Global ignore patterns for your system can go in a file named what ever you wish.

Mine personally is called ~/.gitglobalignore

I can then let git know of this file by editing my ~/.gitconfig file with the following line:

core.excludesfile = ~/.gitglobalignore

You're done!

I find the gitignore man page to be the best resource for more information.

Answer 6

git status is your friend, use it often. Good for answering questions like:

• What did that command just do?
• What branch am I on?
• What changes am I about to commit, and have I forgotten anything?
• Was I in the middle of something last time I worked on this project (days, weeks, or perhaps months ago)?

Unlike, say svn status, git status runs nigh-instantly even on large projects. I often found it reassuring while learning git to use it frequently, to make sure my mental model of what was going on was accurate. Now I mostly just use it to remind myself what I've changed since my last commit.

Obviously, it's much more useful if your .gitignore is sanely configured.

Answer 7

How do you create a new project/repository?

A git repository is simply a directory containing a special .git directory.

This is different from "centralised" version-control systems (like subversion), where a "repository" is hosted on a remote server, which you checkout into a "working copy" directory. With git, your working copy is the repository.

Simply run git init in the directory which contains the files you wish to track.

For example,

cd ~/code/project001/
git init

This creates a .git (hidden) folder in the current directory.

To make a new project, you would made a new directory and run git init in this:

cd ~/code/
mkdir project002
cd project002
git init

To check if the current current path is within a git repository, simply run git status - if it's not a repository, it will report "fatal: Not a git repository"

You could also list the .git directory, and check it contains files/directories similar to the following:

$ ls .git
HEAD         config       hooks/       objects/
branches/    description  info/        refs/

---

If for whatever reason you wish to "de-git" a repository (you wish to stop using git to track that project). Simply remove the .git directory at the base level of the repository.

cd ~/code/project001/
rm -rf .git/

Caution: This will destroy all revision history, all your tags, everything git has done. It will not touch the "current" files (the files you can currently see), but previous changes, deleted files and so on will be unrecoverable!

Answer 8

How do you 'tag' a particular set of revisions

How do you 'mark' 'tag' or 'release' a particular set of revisions for a particular set of files so you can always pull that one later?

Using the git tag command.

To simply "tag" the current revision, you would just run..

git tag -a thetagname
git tag -a 0.1
git tag -a 2.6.1-rc1 -m 'Released on 01/02/03'

To list the current tags, simply run git tag with no arguments, or -l (lower case L):

$ git tag -a thetagname # and enter a message, or use -m 'My tag annotation'
$ git tag -l
thetagname

To delete a tag, you use the -d flag:

$ git tag -d thetagname 
Deleted tag 'thetagname'
$ git tag
[no output]

To tag a specific (previous) commit, you simply do..

git tag [tag name] [revision SHA1 hash]

For example:

git tag 1.1.1 81b15a68c6c3e71f72e766931df4e6499990385b

---

Note: by default, git creates a "lightweight" tag (basically a reference to a specific revision). The "right" way is to use the -a flag. This will launch your editor asking for a tag message (identical to asking for a commit message, you can also use the -m flag to supply the tag message on the command line). Using an annotated tag creates an object with its own ID, date, tagger (author), and optionally a GPG signature (using the -s tag). For further information on this, see this post

git tag mytagwithmsg -a -m 'This is a tag, with message'

And to list the tags with annotations, use the -n1 flag to show 1 line of each tag message (-n245 to show the first 245 lines of each annotation, and so on):

$ git tag -l -n1
mytagwithmsg    This is a tag, with message

For more information, see the git-tag(1) Manual Page

Answer 9

Console UI - Tig

Installation:

apt-get install tig

Usage

While inside a git repo, type 'tig', to view an interactive log, hit 'enter' on any log to see more information about it. h for help, which lists the basic functionality.

Trivia

"Tig" is "Git" backwards.

Answer 10

GUIs for git

---

Git GUI

Included with git - Run git gui from the command line, and the Windows msysgit installer adds it to the Start menu.

Git GUI can do a majority of what you'd need to do with git. Including staging changes, configuring git and repositories, pushing changes, creating/checkout/deleting branches, merging, and many other things.

One of my favourite features is the "stage line" and "stage hunk" shortcuts in the right-click menu, which lets you commit specific parts of a file. You can achieve the same via git add -i, but I find it easier to use.

It isn't the prettiest application, but it works on almost all platforms (being based upon Tcl/Tk)

Screenshots | a screencast

---

GitK

Also included with git. It is a git history viewer, and lets you visualise a repositories history (including branches, when they are created, and merged). You can view and search commits

Goes together with git-gui nicely

---

Gitnub

Mac OS X application. Mainly an equivalent of git log, but has some integration with github (like the "Network view")

Looks pretty, and fits with Mac OS X. You can search repositories. The biggest critisism of Gitnub is that it shows history in a linear fashion (a single branch at a time) - it doesn't visualise branching and merging, which can be important with git, although this is a planned improvement.

Download links, change log and screenshots | git repository

---

GitX

Intends to be a "gitk clone for OS X".

It can visualise non-linear branching history, perform commits, view and search commits, and it has some other nice features like being able to "Quicklook" any file in any revision (press space in the file-list view), export any file (via drag and drop)

Although it is currently still "under development", it is quite usable, and again far better integrated into OS X than git-gui/gitk

Download | Screenshots | git repository

---

SmartGit

From the homepage:

SmartGit is a front-end for the distributed version control system Git and runs on Windows, Mac OS X and Linux. SmartGit is intended for developers who prefer a graphical user interface over a command line client, to be even more productive with Git — the most powerful DVCS today.

You can download it from their website.

Download

---

TortoiseGit

TortoiseSVN Git version for Windows users.

It is porting TortoiseSVN to TortoiseGit The latest release 1.2.1.0 This release can complete regular task, such commit, show log, diff two version, create branch and tag, Create patch and so on. See ReleaseNotes for detail. Welcome to contribute this project.

Download

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QGit

QGit is a git GUI viewer built on Qt/C++.

With qgit you will be able to browse revisions history, view patch content and changed files, graphically following different development branches.

Download

---

gitg

gitg is a git repository viewer targeting gtk+/GNOME. One of its main objectives is to provide a more unified user experience for git frontends across multiple desktops. It does this not be writing a cross-platform application, but by close collaboration with similar clients for other operating systems (like GitX for OS X).

Features

• Browse revision history
• Handle large repositories (loads linux repository, 17000+ revisions, under 1 second)
• Commit changes
• Stage/unstage individual hunks
• Revert changes
• Show colorized diff of changes in revisions
• Browse tree for a given revision
• Export parts of the tree of a given revision
• Supply any refspec which a command such as 'git log' can understand to built the history
• Show and switch between branches in the history view

Download: releases or source

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Gitbox

Gitbox is a Mac OS X graphical interface for Git version control system. In a single window you see branches, history and working directory status.

Everyday operations are easy: stage and unstage changes with a checkbox. Commit, pull, merge and push with a single click. Double-click a change to show a diff with FileMerge.app.

Download

---

Gity

The Gity website doesn't have much information, but from the screenshots on there it appears to be a feature rich open source OS X git gui.

Download or source

---

Meld

Meld is a visual diff and merge tool. You can compare two or three files and edit them in place (diffs update dynamically). You can compare two or three folders and launch file comparisons. You can browse and view a working copy from popular version control systems such such as CVS, Subversion, Bazaar-ng and Mercurial [and Git].

Downloads

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Katana

A Git gui for OSX by Steve Dekorte.

At a glance, see which remote branches have changes to pull and local repos have changes to push. The git ops of add, commit, push, pull, tag and reset are supported as well as visual diffs and visual browsing of project hieracy that highlights local changes and additions.

Free for 1 repository, $25 for more.

Download

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Git Extensions

Open Source for Windows - installs everything you need to work with Git in a single package, easy to use.

Git Extensions is a toolkit to make working with Git on Windows more intuitive. The shell extension will intergrate in Windows Explorer and presents a context menu on files and directories. There is also a Visual Studio plugin to use git from Visual Studio.

Download

---

Big thanks to dbr for elaborating on the git gui stuff.

Answer 11

Resource: Definitely check out Scott Chacon's Gitcasts, especially the Railsconf talk.

Github is awesome and also has some helpful guides.

Answer 12

Push and pull changes

In an simplified way, just do git push and git pull. Changes are merged and if there's a conflict git will let you know and you can resolve it manually.

When you first push to a remote repository you need to do a git push origin master (master being the master branch). From then on you just do the git push.

Push tags with git push --tags.

Answer 13

How to install Git

On Windows:

Install msysgit

This also installs a Cygwin bash shell, so you can use the git in a nicer shell (than cmd.exe), and also includes git-gui (accessible via git gui command, or the Start > All Programs > Git menu)

Mac OS X

Use the git-osx-installer, or you can also install from source

Via a package manager

Install git using your native package manager. For example, on Debian (or Ubuntu):

apt-get install git-core

Or on Mac OS X, via MacPorts:

sudo port install git-core+bash_completion+doc

…or fink:

fink install git

…or Homebrew:

brew install git

On Red Hat based distributions, such as Fedora:

yum install git

In Cygwin the Git package can be found under the "devel" section

From source (Mac OS X/Linux/BSD/etc.)

In Mac OS X, if you have the Developer Tools installed, you can compile Git from source very easily. Download the latest version of Git as a .tar.bz or .tar.gz from http://git-scm.com/, and extract it (double click in Finder)

On Linux/BSD/etc. it should be much the same. For example, in Debian (and Ubuntu), you need to install the build-essential package via apt.

Then in a Terminal, cd to where you extracted the files (Running cd ~/Downloads/git*/ should work), and then run..

./configure && make && sudo make install

This will install Git into the default place (/usr/local - so git will be in /usr/local/bin/git)

It will prompt you to enter your password (for sudo), this is so it can write to the /usr/local/ directory, which can only be accessed by the "root" user so sudo is required!

If you with to install it somewhere separate (so Git's files aren't mixed in with other tools), use --prefix with the configure command:

./configure --prefix=/usr/local/gitpath
make
sudo make install

This will install the git binary into /usr/local/bin/gitpath/bin/git - so you don't have to type that every time you, you should add into your $PATH by adding the following line into your ~/.profile:

export PATH="${PATH}:/usr/local/bin/gitpath/bin/"

If you do not have sudo access, you can use --prefix=/Users/myusername/bin and install into your home directory. Remember to add ~/bin/ to $PATH

The script x-git-update-to-latest-version automates a lot of this:

This script updates my local clone of the git repo (localy at ~/work/track/git), and then configures, installs (at /usr/local/git-git describe) and updates the /usr/local/git symlink.

This way, I can have /usr/local/git/bin in my PATH and I'm always using the latest version.

The latest version of this script also installs the man pages. You need to tweak your MANPATH to include the /usr/local/git/share/man directory.

Answer 14

Git Reset

Say you make a pull, merge it into your code, and decide you don't like it. Use git-log, or tig, and find the hash of wherever you want to go back to (probably your last commit before the pull/merge) copy the hash, and do:

# Revert to a previous commit by hash:
git-reset --hard <hash>

Instead of the hash, you can use HEAD^ as a shortcut for the previous commit.

# Revert to previous commit:
git-reset --hard HEAD^

Answer 15

Checking Out Code

First go to an empty dir, use "git init" to make it a repository, then clone the remote repo into your own.

git clone [email protected]:/dir/to/repo

Wherever you initially clone from is where "git pull" will pull from by default.

Answer 16

WRT good GUIs/frontends, you may also want to check out qgit which is a cross-platform (Linux/Win32) repository viewer for Git and can be also used as high level frontend for the most common Git operations, in fact it can be easily enhanced by so called "custom actions" so that users can provide customized actions.

Answer 17

I got started with the official Git tutorial. I think it's practical enough for beginners (I was, and still am, a beginner, by your definition! I barely grasp makefiles, I've only played a bit with Apache Subversion, etc.).

Answer 18

How do you branch?

The default branch in a git repository is called master.

To create a new branch use

git branch <branch-name>

To see a list of all branches in the current repository type

git branch

If you want to switch to another branch you can use

git checkout <branch-name>

To create a new branch and switch to it in one step

git checkout -b <branch-name>

To delete a branch, use

git branch -d <branch-name>

To create a branch with the changes from the current branch, do

git stash
git stash branch <branch-name>

Answer 19

How do you merge branches?

If you want to merge a branch (e.g. master to release), make sure your current branch is the target branch you'd like to merge into (use git branch or git status to see your current branch).

Then use

git merge master

(where master is the name of the branch you want to merge with the current branch).

If there are any conflicts, you can use

git diff

to see pending conflicts you have to resolve.

Answer 20

I found this post to be very useful to get me started. I still need to read the book and other resources but the post was helpful in, as the title says, "understanding git conceptually". I also recommend taking the Git & GitHub course offered at RubyLearning.

Answer 21

Getting the latest Code

$ git pull <remote> <branch> # fetches the code and merges it into 
                             # your working directory
$ git fetch <remote> <branch> # fetches the code but does not merge
                              # it into your working directory

$ git pull --tag <remote> <branch> # same as above but fetch tags as well
$ git fetch --tag <remote> <branch> # you get the idea

That pretty much covers every case for getting the latest copy of the code from the remote repository.

Answer 22

Seriously add the link featured in Tim's answer in the Stack Overflow post Setup Git Server with Msysgit on Windows.

It flawlessly told me how to setup Git on Windows with msysgit, and is an incredibly detailed article.

Answer 23

How to track remote branches

Assuming there is a remote repository that you cloned your local repository from and also assuming that there is a branch named 'some_branch' on that remote repository, here is how to track it locally:

# list remote branches
git branch -r

# start tracking one remote branch
git branch --track some_branch origin/some_branch

# change to the branch locally
git checkout some_branch

# make changes and commit them locally
....

# push your changes to the remote repository:
git push

Answer 24

How can I create a branch on a remote repository?

Assuming that you have cloned your remote repository from some single remote repository.

# create a new branch locally
git branch name_of_branch
git checkout name_of_branch
# edit/add/remove files    
# ... 
# Commit your changes locally
git add fileName
git commit -m Message
# push changes and new branch to remote repository:
git push origin name_of_branch:name_of_branch

Answer 25

I've also found Git Internals to be very useful. It is written by Scott Chacon (author of Pro Git, and maintainer of the Git Community Book). What I like about Git Internals is it focuses on the concepts first and then the commands, and being that it is ~100 small pages it is quickly digestible.

Answer 26

A real good paper for understanding how Git works is The Git Parable. Very recommended!

Answer 27

How do you compare two revisions of a file, or your current file and a previous revision?

Compare command is git diff.

To compare 2 revisions of a file:

$ git diff <commit1> <commit2> <file_name>

That diffs commit1 against commit2; if you change order then files are diffed the other way round, which may not be what you expect...

To compare current staged file against the repository:

$ git diff --staged <file_name>

To compare current unstaged file against the repository:

$ git diff <file_name>

Answer 28

How do you see the history of revisions to a file?

git log -- filename

Answer 29

Gity: http://macendeavor.com/gity

Answer 30

Here's a copy of PJ Hyett's post, as it is not available anymore:

Git Isn't Hard

Nov 23, 2008

When we tell people why they should use Git over Subversion, the go-to line is, “Git does Subversion better than Subversion, but it does a lot more than that.”

The “lot more” is comprised of a bunch of stuff that makes Git really shine, but it can be pretty overwhelming for those coming from other SCM’s like Subversion.

That said, there’s nothing stopping you from using Git just like you use Subversion while you’re making the transition.

Assuming you’ve installed the necessary software and have a remote repository somewhere, this is how you would grab the code and push your changes back with Subversion:

$ svn checkout svn://foo.googlecode.com/svn/trunk foo
# make your changes
$ svn commit -m "my first commit"

And how would you do it in Git:

$ git clone [email protected]:pjhyett/foo.git
# make your changes
$ git commit -a -m "my first commit"
$ git push

One more command to make it happen in Git. That extra command has large implications, but for the purposes of this post, that’s all we’re talking about, one extra command.

See, it really isn’t that hard.

Update: I’d be remiss to not also mention that the equivalent of updating your local copy in Subversion compared to Git is svn update and git pull, respectively. Only one command in both cases.

Answer 31

How do you set up a shared team repository?

How to set up a normal repository is described here -- but how do you set up a team repository that everybody can pull and push from and to?

Using a shared NFS file system

Assuming your team already has for instance a shared group membership that can be used.

mkdir /your/share/folder/project.git
cd /your/share/folder/project.git
newgrp yourteamgroup # if necessary
git init --bare --shared

To start using this repository the easiest thing to do is start from a local repository you already have been using:

cd your/local/workspace/project
git remote add origin /your/share/folder/project.git
git push origin master

Others can now clone this and start working:

cd your/local/workspace
git clone /your/share/folder/project.git

Using SSH

Set up a user account on the target server. Whether you use an account with no password, an account with a password, or use authorized_keys really depend on your required level of security. Take a look at Configuring Git over SSH for some more information.

If all developers use the same account for accessing this shared repository, you do not need to use the --shared option as above.

After initing the repository in the same way as above, you do the initial push like this:

cd your/local/workspace/project
git remote add origin user@server:/path/to/project.git
git push origin master

See the similarity with the above? The only thing that might happen in addition is SSH asking for a password if the account has a password. If you get this prompt on an account without a password the SSH server probably has disabled PermitEmptyPasswords.

Cloning now looks like this:

cd your/local/workspace
git clone user@server:/path/to/project.git

Answer 32

The Pro Git free book is definitely my favorite, especially for beginners.