# Patching ## git apply ### Description It is used to apply a patch to files and/or to the index. Patches are typically created using the `git diff` or `git format-patch` commands and can represent changes between different states of the repository. This command allows to take these patches and apply them to your working directory or staging area. ### Usage ```sh git apply [] [...] ``` #### Options `--check`: Check if the patch can be applied cleanly without actually applying it. `--index`: Apply the patch to the index (staging area) as well as the working directory. `--reverse`: Apply the patch in reverse (undo the changes). `--whitespace=`: Handle whitespace errors; `` can be `nowarn`, `warn`, `fix`, or `error` `--reject`: Leave the rejected hunks in corresponding `.rej` files instead of applying them partially. `--apply`: Explicitly apply the patch (default action). ``` git apply --check patchfile.patch git apply --index patchfile.patch git apply --reverse patchfile.patch git apply --whitespace=fix patchfile.patch git apply --reject patchfile.patch git apply --apply patchfile.patch ``` ### What It Does 1. **Applies Patches**: Reads a patch file and applies the changes it contains to the working directory or index. 2. **Supports Various Options**: Allows for customization of how the patch is applied, such as applying it in reverse or with fuzz tolerance. ### Common Use Cases ``` -- Apply a Patch to the Working Directory -- Applies the changes in patchfile.patch to the files in the working directory git apply patchfile.patch -- Apply a Patch with Fuzz Tolerance -- Applies the patch even if there are minor differences (fuzz tolerance) and fixes whitespace errors. git apply --apply --whitespace=fix patchfile.patch -- Dry Run -- Checks if the patch can be applied cleanly without actually applying it. git apply --check patchfile.patch ``` ### Example Workflow ``` -- Create a patch file using git diff or git format-patch -- This creates a patch file with the current differences in the working directory. git diff > my_changes.patch -- Apply the Patch -- Applies the changes from my_changes.patch to your working directory git apply my_changes.patch -- Check Before Applying -- checks if the patch can be applied cleanly without actually applying it git apply --check my_changes.patch -- Fix Whitespace Errors -- applies the patch and fixes any whitespace errors encountered git apply --whitespace=fix my_changes.patch ``` ### Example Output When running `git apply patchfile.patch.` This indicates that the patch could not be applied cleanly to `file.c` at line 10.
## git am ### Description It is used to apply patches from email files. It stands for "apply mailbox" and is typically used to apply patches generated by `git format-patch`, which creates email-like formatted patches. This command is particularly useful for applying a series of patches sent via email or saved in mailbox format. ### Usage ```sh git am [] [(|...)] ``` #### Options `-3` or `--3way`: Use 3-way merge if the patch fails to apply cleanly. `-s` or `--signoff`: Add a Signed-off-by line to the commit message. `-skip`: Skip the current patch and continue with the next one `--abort`: Restore the original branch and abort the patch application `--continue`: Continue applying patches after resolving conflicts. `-q` or `--quiet`: Suppress all output. `--interactive`: Allow user to interactively review and edit the patch before applying it. ``` git am -3 patchfile.mbox git am -s patchfile.mbox git am --skip git am --abort git am --continue git am -q patchfile.mbox git am --interactive patchfile.mbox ``` ### What It Does 1. **Applies Patches**: Reads one or more email formatted patches and applies them sequentially to the current branch. 2. **Commits the Changes**: Each patch is applied and committed, retaining the original commit message, author information, and timestamp. {% hint style="info" %} **Handling Conflicts**: If a patch fails to apply cleanly, resolve the conflicts manually, then use `git am --continue` to proceed. If you decide not to apply the patch, use `git am --skip` to skip it or `git am --abort` to abort the process altogether. **Creating Patches**: Use `git format-patch` to generate patches that are compatible with `git am`. This ensures the patches have the correct email-like format. ``` git format-patch -1 HEAD ``` {% endhint %} ### Common Use Cases ``` -- Apply a Single Patch File -- Applies the patch in patchfile.mbox to the current branch git am patchfile.mbox -- Apply Multiple Patch Files -- Applies patch1.mbox and patch2.mbox sequentially to the current branch git am patch1.mbox patch2.mbox -- Apply All Patches in a Directory -- Applies all patches in the specified directory git am /path/to/patches/* ``` ### Example Workflow ``` -- Create Patches Using git format-patch -- This creates email formatted patch files for the specified commit range git format-patch -n -- Apply the Patches -- Applies all patch files in the current directory git am *.patch -- Resolve Conflicts and Continue -- If a patch fails to apply cleanly, resolve the conflicts manually, then run git am --continue -- Abort the Patch Application -- If we want to abort the process and revert to the original state git am --abort ``` ### Example Output When running `git am patchfile.mbox`
If a patch fails to apply cleanly
--- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://www.pranaypourkar.co.in/the-programmers-guide/git/commands/patching.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.