pre-commit
- Git course
- Advanced
- Lesson 22/56
- 4 min
Learn pre-commit checks with the pre-commit hook.
What Is the pre-commit Hook?
The pre-commit hook runs immediately before Git creates a commit. You can perform checks such as code formatting, whitespace validation, and basic verification at this stage. If the hook exits with a failure status, Git stops the commit operation.
#!/bin/sh
# Check before commit
if [ -f "ERROR.txt" ]; then
echo "Validation failed"
exit 1
fiValidation and Exit Status
A hook script usually returns 0 when successful and a nonzero exit code when it fails. The exit 1 command tells Git that the check was unsuccessful. This lets you prevent a commit when a required validation does not pass.
#!/bin/sh
if [ ! -f "README.md" ]; then
echo "README is missing"
exit 1
fi
exit 0This check stops the commit when the README file is missing.
Practice Check a File Before Committing
Create a pre-commit script. If README.md does not exist, print an error message and terminate with exit 1. If the file exists, use exit 0.
Starter code
# README dosyasını kontrol et
# Eksikse hata döndür
# Varsa başarılı çıkSample solution
if [ ! -f "README.md" ]; then
echo "README.md eksik"
exit 1
fi
exit 0Expected output
README.md eksik
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 At which stage does the pre-commit hook run?
- After a push to the remote repository is completed
- When the repository is cloned for the first time
- Before a commit is created Correct answer
- After a commit has been successfully created
Explanation: pre-commit is triggered before the commit is created and can prevent the operation if it fails.
2 Report a Failed Check
#!/bin/sh
____#!/bin/sh
exit 1Explanation: <code>exit 1</code> terminates the script with a failure status and prevents the commit operation.
3 pre-commit Components
| Term | Meaning |
|---|---|
pre-commit |
Runs before a commit |
exit 0 |
Successful exit |
exit 1 |
Failure exit |
README kontrolü |
Validates a required file |