git pull远程分支V / S git merge远程/分支V / S git rebase远程/分支

Question

Consider my forked repo is mapped with the remote origin and the parent repo mapped to upstream .

Seems like, all the 3 commands below can be used to keep the master branch of origin , up to date with the master branch of upstream .

git pull upstream master

git merge upstream/master

git rebase upstream/master

Please help me understand if there are any differences between these three commands.

Answer 1

The output of merge and pull is the same in the sense that changes from the merged branch is applied on top of current commits in your current branch.

Before pull /merge

  A---B---C master on origin
 /
D---E---F---G master

After

  A---B---C origin/master
 /         \
D---E---F---G---H master

The output of rebase is reverse of pull. All the new commits from the point the current branch is created is shelved. The commits from the remote branch is applied and then the local commits are applied. So compared to pull the local commits are at the end of commits of remote.

     A---B---C topic
     /
D---E---F---G master

After rebase command

              A'--B'--C' topic
             /
D---E---F---G master

Source - https://git-scm.com/docs/git-rebase