What is the difference between 'git pull' and 'git fetch'?

Answer 1

This interactive graphical representation is very helpful in understanging git: http://ndpsoftware.com/git-cheatsheet.html

git fetch just "downloads" the changes from the remote to your local repository. git pull downloads the changes and merges them into your current branch. "In its default mode, git pull is shorthand for git fetch followed by git merge FETCH_HEAD."

Answer 2

The Difference between GIT Fetch and GIT Pull can be explained with the following scenario: (Keeping in mind that pictures speak louder than words!, I have provided pictorial representation)

Let's take an example that you are working on a project with your team members. So there will be one main Branch of the project and all the contributors must fork it to their own local repository and then work on this local branch to modify/Add modules then push back to the main branch.

So, Initial State of the two Branches when you forked the main project on your local repository will be like this- (A, B and C are Modules already completed of the project)

Now, you have started working on the new module (suppose D) and when you have completed the D module you want to push it to the main branch, But meanwhile what happens is that one of your teammates has developed new Module E, F and modified C.
So now what has happened is that your local repository is lacking behind the original progress of the project and thus pushing of your changes to the main branch can lead to conflict and may cause your Module D to malfunction.

To avoid such issues and to work parallel with the original progress of the project there are Two ways:

1. Git Fetch- This will Download all the changes that have been made to the origin/main branch project which are not present in your local branch. And will wait for the Git Merge command to apply the changes that have been fetched to your Repository or branch.

So now You can carefully monitor the files before merging it to your repository. And you can also modify D if required because of Modified C.

2. Git Pull- This will update your local branch with the origin/main branch i.e. actually what it does is a combination of Git Fetch and Git merge one after another. But this may Cause Conflicts to occur, so it’s recommended to use Git Pull with a clean copy.

Answer 3

I like to have some visual representation of the situation to grasp these things. Maybe other developers would like to see it too, so here's my addition. I'm not totally sure that it all is correct, so please comment if you find any mistakes.

                                         LOCAL SYSTEM
                  . =====================================================    
================= . =================  ===================  =============
REMOTE REPOSITORY . REMOTE REPOSITORY  LOCAL REPOSITORY     WORKING COPY
(ORIGIN)          . (CACHED)           
for example,      . mirror of the      
a github repo.    . remote repo
Can also be       .
multiple repo's   .
                  .
                  .
FETCH  *------------------>*
Your local cache of the remote is updated with the origin (or multiple
external sources, that is git's distributed nature)
                  .
PULL   *-------------------------------------------------------->*
changes are merged directly into your local copy. when conflicts occur, 
you are asked for decisions.
                  .
COMMIT            .                             *<---------------*
When coming from, for example, subversion, you might think that a commit
will update the origin. In git, a commit is only done to your local repo.
                  .
PUSH   *<---------------------------------------*
Synchronizes your changes back into the origin.

Some major advantages for having a fetched mirror of the remote are:

• Performance (scroll through all commits and messages without trying to squeeze it through the network)
• Feedback about the state of your local repo (for example, I use Atlassian's SourceTree, which will give me a bulb indicating if I'm commits ahead or behind compared to the origin. This information can be updated with a GIT FETCH).

Answer 4

What is the difference between git pull and git fetch?

To understand this, you first need to understand that your local git maintains not only your local repository, but it also maintains a local copy of the remote repository.

git fetch brings your local copy of the remote repository up to date. For example, if your remote repository is GitHub - you may want to fetch any changes made in the remote repository to your local copy of it the remote repository. This will allow you to perform operations such as compare or merge.

git pull on the other hand will bring down the changes in the remote repository to where you keep your own code. Typically, git pull will do a git fetch first to bring the local copy of the remote repository up to date, and then it will merge the changes into your own code repository and possibly your working copy.

Answer 5

Here is Oliver Steele's image of how all it all fits together:

If there is sufficient interest, I suppose I could update the image to add git clone and git merge...

Answer 6

git fetch pulls down the code from the remote server to your tracking branches in your local repository. If your remote is named origin (the default) then these branches will be within origin/, for example origin/master, origin/mybranch-123, etc. These are not your current branches, they are local copies of those branches from the server.

git pull does a git fetch but then also merges the code from the tracking branch into your current local version of that branch. If you're not ready for that changes yet, just git fetch first.