Node PM2 process manager

Command	Description
pm2 start file-name.js	runs a process with single file file-name.js using pm2

Docker

Command	Description
$ docker ps	List only running docker containers (CONTAINER_ID, IMAGE, COMMAND, CREATED, STATUS, PORTS, NAMES)
$ docker ps -a	List all running and stopped docker containers (CONTAINER_ID, IMAGE, COMMAND, CREATED, STATUS, PORTS, NAMES)
$ docker restart NAME_OR_CONTAINER_ID	Restart docker container with CONTAINER_ID, data does not vanish. Combination of 2 commands docker stop and docker start
$ docker stop NAME_OR_CONTAINER_ID	Stop docker container with CONTAINER_ID, data does not vanish.
$ docker start NAME_OR_CONTAINER_ID	Start docker container with CONTAINER_ID, data does not vanish.
$ docker logs --tail 100 NAME_OR_CONTAINER_ID	Inspect the last 100 lines of the logs with CONTAINER_ID
$ docker logs -f --tail 100 NAME_OR_CONTAINER_ID	Inspect the last 100 lines of the logs with CONTAINER_ID, also enter in -f follow mode, i.e. streams the logs in real-time
$ docker logs -t --tail 100 NAME_OR_CONTAINER_ID	Inspect the last 100 lines of the logs with CONTAINER_ID, also show timestamp -t
$ docker logs -tfn 100 NAME_OR_CONTAINER_ID	Inspect the last 100 lines of the logs with CONTAINER_ID, also show timestamp -t and follow output (combined command of several options)
$ docker inspect NAME_OR_CONTAINER_ID	Retrieving low-level information about Docker objects (by default in JSON array format). Provides a comprehensive view of various Docker constructs (Container: ID, name, Mounted volumes and bind mounts, Log path, Network settings, CPU, memory; Images; Networks; Volumes; etc.)

NGINX Commands

Command	Description
$ sudo systemctl reload nginx	This is the most common and recommended command after making changes to your Nginx configuration files. It reloads the configuration without dropping active connections. Nginx will: 1. Test the new configuration syntax. 2. If the syntax is OK, it starts new worker processes with the new configuration. 3. Gracefully shuts down the old worker processes (allowing them to finish serving current requests).
$ sudo nginx -t	Test Nginx Configuration Syntax. This is crucial before reloading or restarting Nginx. It checks the syntax of your Nginx configuration files and also verifies if any referenced files (like SSL certificates) exist and are accessible. It will report "syntax is ok" and "test is successful" if everything is good. If there are errors, it will pinpoint them.
$ ls -l /etc/nginx/	default location of NGINX config files

Linux Commands

Command	Description
$ mv PATH_TO_FILE PATH_TO_FOLDER_TO_MOVE	Moves file into directory. The file will disappear from original PATH_TO_FILE file path and be moved to PATH_TO_FOLDER_TO_MOVE directory
$ ls -l path/to/directory	Lists contents of the directory without actually changing directory. Good for quick inspection
$ netstat -tulpn | grep ":PORT"	lists all processes/programs PID that listen on port PORT (ex, 18084)
$ man PROGRAM_NAME	shows details of the command such as SYNOPSIS, DESCRIPTION, OPTIONS

Let's Encrypt with Certbot

Command	Description
$ certbot certificates	List the Certificates to Find the Certificate Name: Run this command to view all certificates managed by Certbot. This will display a list of certificates, showing the certificate name (under "Certificate Name") for each one.
$ certbot renew --dry-run	You the command to test whether the TLS certificate renew is working properly, whether there are any errors in the command, etc., without actually updating.
$ certbot renew --cert-name yourdomain.com	Renew the Certificate for a Specific Domain: Once you know the "certificate name", use the --cert-name option to renew only that specific certificate.
$ certbot certonly --standalone -d www.eduhere.co.kr -d eduhere.co.kr	Use the --standalone option to tell Certbot to handle the challenge using its own built-in web server. It generates and saves the certificate files in the /etc/letsencrypt/live/your_domain directory, but you must then manually install these files with your web server (like Nginx or Apache) and configure it to use the new certificate. Also, the nginx server reload should be performed after configuring nginx server

Key Generation & Management (openssl, ssh-keygen, ...)

Command	Description
$ openssl rsa -in jwtRS256.key -pubout -out jwtRS256.key.pub	Generates public key in SPKI format (into file path jwtRS256.key.pub) from private key in PEM format (file path jwtRS256.key)
$ ssh-keygen -t rsa -P '""' -b 2048 -m PEM -f jwtRS256.key	Generates the RSA Private Key in PEM format into jwtRS256.key file
$ ssh-keygen -e -m PEM -f jwtRS256.key > jwtRS256.key.pub	Generates the RSA Public Key (into jwtRS256.key.pub) from Private Key in PEM format (from jwtRS256.key)

Databases (Mysql, Postgre, etc.)

Command	Description
$ mysqldump -u root -p mydatabase > backup_$(date +%Y%m%d_%H%M%S).sql	Backup MySQL database with timestamp and mysqldump utility
$ mysqldump -u root -p --all-databases > full_backup_$(date +%Y%m%d_%H%M%S).sql	Backup MySQL all database with timestamp and mysqldump utility