How to use the command pre-commit (with examples)
The pre-commit command is a tool that allows you to create Git hooks that run before a commit. It helps ensure that certain checks or validations are performed before code is committed, improving code quality and reducing the likelihood of introducing bugs or issues. This command can be particularly useful in multi-developer projects where consistency and adherence to development standards are important.
Use case 1: Install pre-commit into your Git hooks
Code:
pre-commit install
Motivation: Installing pre-commit into your Git hooks is the first step in incorporating pre-commit checks into your workflow. By running this command, pre-commit will be initialized in the .git/hooks folder of your repository, allowing it to intercept the commit process and trigger the configured hooks.
Explanation:
pre-commit install: This command installs pre-commit into the Git hooks of your repository.
Example output:
pre-commit installed at .git/hooks/pre-commit
Use case 2: Run pre-commit hooks on all staged files
Code:
pre-commit run
Motivation: Running pre-commit hooks on all staged files allows you to check for issues in the code that is about to be committed. This helps ensure that any potential issues are identified and addressed before the code is added to the Git repository.
Explanation:
pre-commit run: This command runs pre-commit hooks on all files that are currently staged for commit.
Example output:
Trim Trailing Whitespace............................................................Passed
Check for added large files.........................................................Passed
Run Flake8 linter..................................................................Passed
Run isort linter..................................................................Passed
Run black linter...................................................................Passed
Use case 3: Run pre-commit hooks on all files, staged or unstaged
Code:
pre-commit run --all-files
Motivation: Running pre-commit hooks on all files, staged or unstaged, allows you to perform comprehensive code checks and validations across your entire project. This is particularly useful when adding new files or making changes to existing files that are not yet staged for commit.
Explanation:
pre-commit run: This command runs pre-commit hooks on both staged and unstaged files.--all-files: This option instructs pre-commit to include all files in the execution, regardless of their staging status.
Example output:
Trim Trailing Whitespace............................................................Passed
Check for added large files.........................................................Passed
Run Flake8 linter..................................................................Passed
Run isort linter..................................................................Passed
Run black linter..................................................................Passed
Use case 4: Clean pre-commit cache
Code:
pre-commit clean
Motivation: Cleaning the pre-commit cache is useful when you want to ensure that the latest versions of the pre-commit hooks are used. It removes any cached hooks and forces pre-commit to fetch and re-install the latest versions from the configured sources.
Explanation:
pre-commit clean: This command cleans the pre-commit cache, removing any cached hooks.
Example output:
Cleaning cache at /home/user/.cache/pre-commit
Conclusion:
The pre-commit command is a versatile tool that allows you to incorporate pre-commit checks into your Git workflow. Whether you want to install pre-commit, run hooks on staged or unstaged files, or clean the pre-commit cache, this command provides you with the necessary flexibility to ensure code quality and adherence to development standards. By using pre-commit, you can catch potential issues before they make it into your repository, improving the overall stability and maintainability of your codebase.
