How do I handle the placeholders in commands?

Anything wrapped in angle brackets (e.g. , ) is a placeholder you need to replace. For example, in the MySQL command `SELECT * FROM WHERE id = ;` you should substitute the real table name and ID value. Some parameters are optional (such as --flag options after a command); not every parameter has to be filled in.

Common Commands Cheat Sheet

MySQL / Redis / Nginx / Docker / K8s / Git / Linux / npm / Vim / Maven / Python / HTTP status codes

📌 For MySQL 8.0+

Service Management

sudoLinux Start MySQL Service

sudo systemctl start mysql

Start the MySQL service with systemd (Linux)

sudoLinux Stop MySQL Service

sudo systemctl stop mysql

Stop the MySQL service

sudoLinux Restart MySQL Service

sudo systemctl restart mysql

Restart the MySQL service

sudoLinux Check MySQL Status

sudo systemctl status mysql

Check whether the MySQL service is running

macOS Start with Homebrew (macOS)

brew services start mysql

Start MySQL via Homebrew on macOS

Backup & Restore

Back Up All Databases

mysqldump -u root -p --all-databases > backup.sql

Export all databases to an SQL file

⚠️ Large backups may take a long time

Back Up a Database

mysqldump -u root -p database_name > db_backup.sql

Export the specified database

Restore a Database

mysql -u root -p database_name < backup.sql

Restore a database from an SQL file

Back Up a Single Table

mysqldump -u root -p database_name table_name > table_backup.sql

Export the data and structure of the specified table

User Management

Create a New User

CREATE USER 'username'@'localhost' IDENTIFIED BY 'password';

Create a new MySQL user

Grant All Privileges

GRANT ALL PRIVILEGES ON *.* TO 'username'@'localhost';

Grant the user all privileges on all databases

⚠️ Use the least-privilege principle in production

Flush Privileges

FLUSH PRIVILEGES;

Reload the privilege tables to apply changes

Delete a User

DROP USER 'username'@'localhost';

Delete the specified user

Performance Monitoring

View Running Queries

SHOW FULL PROCESSLIST;

Show all current connection queries

Check Slow Query Log

SHOW VARIABLES LIKE 'slow_query_log';

Check whether the slow query log is enabled

View Database Size

SELECT table_schema AS 'Database', ROUND(SUM(data_length + index_length) / 1024 / 1024, 2) AS 'Size (MB)' FROM information_schema.tables GROUP BY table_schema;

Count the size of each database

📚 More references: MySQL official docs

How to Use

Click a category tab to switch command groups, or use the search box for a fuzzy search. Click the Copy button to copy a command to the clipboard. Commands marked with ⚠️ should be verified in a test environment first, and the <parameter> placeholders in commands should be replaced with real values.

FAQ

Can the commands be copied straight into a terminal?

Yes. Each command has a "Copy" button that copies it to the clipboard. Note, however, that some commands use example formats (placeholders such as <your_password>, <database>), so replace them with real values before running; commands marked ⚠️ (e.g. rm -rf, DROP DATABASE) are risky, so make sure you understand them before running them carefully.

Which tech stacks are covered?

This cheat sheet covers 12 categories of tech stack: MySQL, Redis, Nginx, Docker, Docker Compose, Kubernetes (kubectl), Git, basic Linux commands, npm/npx, the Vim editor, Maven and Python/pip commands, plus common HTTP status codes. Each category is grouped by function and supports cross-category keyword search.

How do I handle the <parameter> placeholders in commands?

Anything wrapped in angle brackets (e.g. <database>, <table>) is a placeholder you need to replace. For example, in the MySQL command `SELECT * FROM <table> WHERE id = <id>;` you should substitute the real table name and ID value. Some parameters are optional (such as --flag options after a command); not every parameter has to be filled in.