Validate the Patch without Applying (Dry-run Patch File)
You can test the patch command without actually modifying any files. This is called a “dry run.” To do a dry run, use the –dry-run option.
Command :
patch --dry-run < patch_file
This will show you what files would be patched, but it won’t make any changes. For example:
Command :
patch --dry-run < hello.patch
patching file hello.c
Output :
After this command, hello.c will remain unchanged. The dry run just simulates what would happen if you applied the patch for real. Doing a dry run allows you to check for any potential errors before permanently modifying your files. If the dry run looks good, you can run the patch command again without –dry-run to actually apply the changes.
How to Run Patch Command in Linux?
Sometimes, you install software by compiling it from source code instead of using package managers like yum or apt-get. When a security fix is available for such software, you can’t just upgrade it like you normally would. Instead, you must download the security patch, apply it to the source code, and then recompile the software.
This article explains how to create and apply the diff and patch commands. A patch file contains the differences between two versions of the same file or source code. It is made using the diff command and applied using the patch command.
Run Patch Command in Linux
- Syntax of running patch command in Linux
- Application of the Patch File
- Options and descriptions for patch command
- Create a Patch File using diff
- Apply Patch File using Patch Command
- Create a Patch From a Source Tree
- Apply Patch File to a Source Code Tree
- Take a Backup before Applying the Patch using -b
- Validate the Patch without Applying (Dry-run Patch File)
- How to Undo/Reverse a Patch