Gitignore is a file used in the Git version control system to specify intentionally untracked files that Git should ignore. This file tells Git which files or directories to exclude from version control when performing operations like commit or push.
History and Development
- Git was created by Linus Torvalds in 2005 for Linux kernel development.
- The concept of ignoring files was introduced early in Git's development to manage temporary files, build artifacts, and other files that should not be tracked.
- The .gitignore file format evolved from simple lists to a more structured syntax over time.
File Format and Syntax
The .gitignore file uses a simple syntax:
- Lines starting with '#' are considered comments.
- Blank lines are ignored.
- Patterns specifying files or directories to ignore are listed, one per line.
- Patterns can include wildcards:
- '*' matches zero or more characters.
- '?' matches exactly one character.
- '**' matches nested directories.
- Patterns can be negated with '!' to make Git track files that would otherwise be ignored.
- Patterns ending with a slash ('/') only match directories.
Usage and Placement
- A .gitignore file can be placed in any directory in a Git repository. The scope of patterns in this file will be limited to that directory and all subdirectories.
- Patterns are matched relative to the location of the .gitignore file.
- Global .gitignore files can be set up to ignore files across all repositories on a system.
Contextual Use
Gitignore is crucial for:
- Keeping sensitive information like API keys out of the repository.
- Excluding build artifacts, logs, IDE configuration files, or any auto-generated files.
- Reducing repository size by not tracking unnecessary files.
- Improving performance by avoiding unnecessary version control operations on large files or frequently changing files.
External Resources
Related Concepts