Duplication: branch
When the project gets bigger, people create more than one branch to hold more versions in parallel. Branches get forked and merged, leading to immensely complicated operations.
To create a new branch at the current commit:
$ git branch <new_branch>
To switch to another branch, thus modifying files in the working tree:
$ git checkout -b <another_branch>
You had better commit new changes before checking out another branch, to prevent current work to be lost. To list all branches, with the current one highlighted with a asterisk:
$ git branch
Combination: merge
To merge two branches into one:
$ git merge <merged_branch>
If there are conflicts, there will be an error message telling you so. Git overwrites the conflicting parts of the file, adding text like this:
<<<<<<<
(text excerpts from to the chief branch being merged into)
|||||||
(text excerpts from to the common ancestor)
=======
(text excerpts from to the feature branch merging into the chief branch)
>>>>>>>
You should replace these lines with what you want. After all conflicts are resolved, add the changes and commit again.
Replay: rebase, cherry-pick
To apply a rebase, in order to replay commits from the current branch onto another branch:
$ git rebase <target_branch>
With option -i, you may edit whether and how the each commit is used.
For concreteness: Let us say you want to combine the last commits to be one. Apply an interactive rebase:
$ git rebase -i HEAD~3 <target_branch>
An editor should open, showing:
pick 12345ab third commit
pick 23456cd second commit
pick 34567ef first commit
Squash the first and second commit, by modifying as thus:
pick 12345ab third commit
squash 23456cd second commit
squash 34567ef first commit
When you close the file, another editor would open just as in commit --amend, where you may edit your message for the new commits.
On the contrary, cherry-pick allows us to choose one commit of another branch, and replay commits from the branching node, onto the current commit.
$ git cherry-pick <commit_being_picked>
❧ February 6, 2017; revised August 1, 2021