What is Patch?
Patch is a code and file update released to fix errors in a software, close security vulnerabilities or improve existing functions.
1. Patch in the World of Software and Games
Traditionally, when an error occurs in a program, downloading and installing the entire software from scratch is inefficient in terms of bandwidth and time. The patch only applies the changed bytes or files to the target system.
- Security Patches: Deployed urgently to close critical security vulnerabilities (CVE) and zero-day vulnerabilities.
- Bug Fixes: Fixes logical errors that disrupt stability or cause unexpected crashes.
- Game Patches and Balancing: These are updates that balance character abilities, add new content, and optimize performance in online multiplayer games. It is usually accompanied by detailed "Patch Notes".
- Hotfix: A narrow-scope patch released immediately to extinguish the fire in the production environment without waiting for the test cycle.
2. Patch in Developer Tools: UNIX patch and Git
In the open source world and version control systems, a patch is a plain text document that represents the difference between two files or commits.
UNIX patch Command and History
Based on the metaphor of covering holes in punched cards with tape or repairing paper strips, the "patch" was standardized in 1985 with the patch command written by Larry Wall. Produced with the command diff -u old.c new.c > fix.patch, the patch can be applied directly to the source code on the receiving end using patch < fix.patch.
Using Patch in Git Environment
Git offers advanced tools for pushing patches through email lists or offline channels:
- git format-patch: Converts specific commits into email-friendly .patch files with author information, commit message, and code diff.
- git apply: Applies a patch file directly to the working directory without creating a commit.
- git am: Reads patches in email format and automatically creates commits with the original author and date (especially standard in Linux kernel development).
3. HTTP PATCH in Web Architecture and REST APIs
PUT and PATCH methods are frequently compared when updating data in RESTful services:
- PUT (Full Replacement): Retransmits the entire source. Unspecified fields are usually reset to default or deleted. The PUT operation is idempotent (sending the same request over and over produces the same result).
- PATCH (Partial Update - RFC 5789): Sends a body containing only the fields that are requested to be changed. For example, to update just a user's email address, instead of sending the entire profile object, it is sufficient to pass only the relevant field.
- JSON Patch (RFC 6902): It is a structure that defines atomic sequences of operations such as add, remove, replace, move, copy and test to standardize changes.
Comparative Summary: "Patch" in Different Contexts
| Context | What Does It Mean? | Main Purpose | Typical Example |
|---|---|---|---|
| Software & Operating System | Update Package | Vulnerability closure, stability | Windows Update KB patch, Zero-day patch |
| Game World | Content and Balance Update | Gameplay balance, performance, meta change | Season patch (Patch 14.2), Balancing update |
| Git & Version Control | Line-Based Change File | Code sharing, code review, contribution | git format-patch HEAD~1 -o linux-kernel.patch |
| Web API / HTTP | Partial Update Method | Network saving, partial change on resource | PATCH /api/users/42 body: {"status": "active"} |
Questions and answers
What does Patch mean? What is its Turkish equivalent?
Its Turkish equivalent is "patch" or "bug patch". It refers to code snippets that repair or update a specific part of a system or software without changing the entire system.
What is the difference between Hotfix and Patch?
Patches are usually released after extensive testing with planned releases (e.g. monthly security bulletins). Hotfix, on the other hand, is an unplanned, rapid intervention patch prepared to immediately stop an emergency crash or security vulnerability that occurs in the production environment.
What is the main difference between HTTP PUT and HTTP PATCH?
PUT aims to completely replace the resource and gives the same result if the same request is repeated (idempotent). PATCH, on the other hand, only partially updates the specified areas of the source (partial update) and does not have to be idempotent in every scenario.
Why are patch files still used when there is a PR (Pull Request) in the Git environment?
Well-established open source projects such as the Linux kernel, Git's own development process, and Postgres maintain an e-mail-based patching workflow in order to avoid dependence on central web platforms (GitHub, etc.).
What is Patch Tuesday?
It is the name given to the industry calendar in which Microsoft regularly distributes bulk security patches for Windows and enterprise products on the second Tuesday of each month.
Related terms
Related tools
This explanation was written in plain language for TreScout with AI and machine-translated from the Turkish original · the Turkish version prevails. If something looks wrong or missing, write to hello@trescout.com. Read in Turkish →