How to use the command 'git merge' (with examples)

The git merge command is used to combine changes from different branches into your current branch. It allows you to integrate the changes made in one branch into another branch.

Use case 1: Merge a branch into your current branch

Code:

git merge branch_name

Motivation: This use case is useful when you want to incorporate the changes made in a specific branch into your current branch. It helps to bring the updated code from another branch into your working branch.

Explanation: The git merge command is followed by the name of the branch that you want to merge into your current branch. In this case, branch_name is the name of the branch that you want to merge.

Example output:

Updating 56a6ddb..1e6e1d3
Fast-forward
 file.txt | 3 +++
 1 file changed, 3 insertions(+)

Use case 2: Edit the merge message

Code:

git merge --edit branch_name

Motivation: This use case allows you to edit the automatic merge message that is generated when you merge the branches. It gives you the flexibility to provide a customized merge message.

Explanation: The git merge --edit command is followed by the name of the branch that you want to merge into your current branch (branch_name). The --edit option allows you to open the merge message in the default text editor for editing.

Example output:

Automatic merge of branch 'branch_name'
Conflicts:
	file.txt

Use case 3: Merge a branch and create a merge commit

Code:

git merge --no-ff branch_name

Motivation: This use case is useful when you want to create a merge commit even if the merge can be fast-forwarded. It helps to keep a track of all the branch merges and provides a clear history of the development process.

Explanation: The git merge --no-ff command is followed by the name of the branch that you want to merge into your current branch (branch_name). The --no-ff option ensures that a merge commit is created even if it can be fast-forwarded.

Example output:

Merge made by the 'recursive' strategy.
 file.txt | 5 +++++
 1 file changed, 5 insertions(+)

Use case 4: Abort a merge in case of conflicts

Code:

git merge --abort

Motivation: This use case is useful when conflicts occur during the merge process and you want to abort the merge operation. It allows you to revert back to the state before the merge.

Explanation: The git merge --abort command aborts the current merge operation. It discards all the changes that were made during the merge process and reverts the branches to the state before the merge.

Example output:

Merge conflict detected. Please resolve conflicts and commit the changes.
Aborting

Use case 5: Merge using a specific strategy

Code:

git merge --strategy strategy --strategy-option strategy_option branch_name

Motivation: This use case is useful when you want to specify a specific merge strategy to be used during the merge operation. It provides more control over how the changes are merged between branches.

Explanation: The git merge --strategy command allows you to specify a merge strategy (strategy) and its options (strategy_option) for merging the changes in the branches. branch_name is the name of the branch that you want to merge.

Example output:

Auto-merging file.txt
CONFLICT (content): Merge conflict in file.txt
Automatic merge failed; fix conflicts and then commit the result.

Conclusion:

The git merge command is a powerful tool that enables you to combine changes from different branches into your current branch. By understanding its various use cases, you can effectively manage the merging process and keep your codebase up to date.