How to use the command git am (with examples)
The git am command is used to apply patch files and create a commit. It is particularly useful when receiving commits via email. It allows for the easy application of patch files and committing the changes in one command. If you need to generate patch files, you can refer to the git format-patch command.
Use case 1: Apply and commit changes following a local patch file
Code:
git am path/to/file.patch
Motivation:
Applying changes from a patch file is a common practice when collaborating on a project. By using git am, you can easily apply the changes specified in the patch file and create a commit with the changes.
Explanation:
git am: The command itself, indicating that we want to apply patch files and create a commit.path/to/file.patch: The path to the patch file that contains the changes to be applied.
Example output:
Applying: Update README.md
Applying: Fix bug in login form
Created commit 1234567: Apply patches
2 files changed, 50 insertions(+), 10 deletions(-)
Use case 2: Apply and commit changes following a remote patch file
Code:
curl -L https://example.com/file.patch | git apply
Motivation:
Sometimes, patch files may be available remotely on a server or through an HTTP URL. In such cases, we can use curl to download the patch file and then apply it using git apply or git am.
Explanation:
curl: A command-line tool used to transfer data.-L: Follow any redirects when downloading the file.https://example.com/file.patch: The URL to the remote patch file.|: A pipe operator used to pass the downloaded patch file to the next command (git apply).
Example output:
Checking patch file1.txt...
Applying: Update file1.txt
Checking patch file2.txt...
Applying: Update file2.txt
2 files changed, 10 insertions(+), 5 deletions(-)
Use case 3: Abort the process of applying a patch file
Code:
git am --abort
Motivation:
There may be times when you realize that you made a mistake while applying a patch file and want to abort the process. The --abort option allows you to do that, reverting any changes made during the apply process.
Explanation:
git am: The command itself, indicating that we want to apply patch files and create a commit.--abort: The option instructing Git to abort the apply process and revert any changes made.
Example output:
Patch application was not started. No changes applied.
Use case 4: Apply as much of a patch file as possible, saving failed hunks to reject files
Code:
git am --reject path/to/file.patch
Motivation:
When applying a patch file, it’s possible that some changes cannot be applied automatically due to conflicts or other issues. The --reject option allows you to save those failed hunks to reject files, giving you the opportunity to manually resolve the conflicts later.
Explanation:
git am: The command itself, indicating that we want to apply patch files and create a commit.--reject: The option instructing Git to save failed hunks to reject files.path/to/file.patch: The path to the patch file that contains the changes to be applied.
Example output:
Applying: Update file1.txt
Updating file1.txt failed. Saving rejects to file1.txt.rej
Applying: Update file2.txt
2 files changed, 10 insertions(+), 5 deletions(-)
Conclusion:
The git am command is a powerful tool for applying patch files and creating commits, especially when collaborating on projects. It allows for easy integration of changes, whether they are local or remote, and provides options for handling conflicts and failed hunks. By understanding the different use cases of git am, you can effectively apply and manage changes in your Git repository.
