Basic commands for Debian system administration

Debian is a Linux operating system widely used on servers and workstations. As a Debian system administrator, it is essential to be familiar with the basic commands to perform maintenance, configuration and monitoring tasks. This manual will provide you with a practical guide to the essential commands that will allow you to efficiently administer and maintain a Debian system.

1. System Information Commands

• uname -a: Displays detailed information about the system, such as kernel name, architecture and hostname.

• lsb_release -a: Displays information about the installed Debian distribution, such as version and description.

• df -h: Displays the used and available disk space on all partitions of the system.

• free -h: Displays the used and available RAM on the system.

2. User and Group Management

• adduser nombre_usuario: Creates a new user in the system.

• usermod -aG grupo nombre_usuario: Adds a user to a specific group.

• deluser nombre_usuario: Remove a user from the system.

• addgroup nombre_grupo: Creates a new group in the system.

3. Package Management

• apt update: Updates the list of available packages in the repositories.

• apt upgrade: Upgrades installed packages to the latest versions.

• apt install nombre_paquete: Installs a specific package.

• apt remove nombre_paquete: Uninstall a package from the system.

• apt search nombre_paquete: Searches for packages related to a specific term.

4. Service Management

• systemctl status nombre_servicio: Shows the status of a service.

• systemctl start nombre_servicio: Starts a service.

• systemctl stop nombre_servicio: Stops a service.

• systemctl restart nombre_servicio: Restart a service.

• systemctl enable nombre_servicio: Enables a service to start automatically on system startup.

• systemctl disable nombre_servicio: Disables a service to start automatically at system startup.

5. Network Configuration

• ifconfig: Displays information about the configured network interfaces.

• ip addr: Displays more detailed information about the network interfaces and their IP addresses.

• ping dirección_ip: Sends ICMP packets to an IP address to verify network connectivity.

• nslookup nombre_host: Performs a DNS query to obtain the IP address associated with a hostname.

6. File and Directory Management

• ls: Lists the contents of the current directory.

• pwd: Displays the path to the current directory.

• cd ruta_directorio: Changes to the specified directory.

• mkdir nombre_directorio: Creates a new directory.

• rm nombre_archivo: Deletes a file.

• rm -r nombre_directorio: Removes a directory and its contents recursively.

7. Compress and Decompress Files

• tar -cvf archivo.tar directorio: Creates a tar archive from a directory.

• tar -xvf archivo.tar: Extracts the contents of a tar archive.

• gzip archivo: Compress a file in gzip format.

• gunzip archivo.gz: Unzip a compressed file in gzip format.

8. Process Management

• ps: Displays a list of the processes currently running on the system.

• ps aux: Displays a more detailed list of all processes in the system, including those of other users.

• top: Provides a dynamic, real-time view of running processes, with regularly updated information.

• htop: An enhanced version of top that displays processes in a more readable format and allows you to interact with them more easily.

• kill PID: Terminates (kills) a specific process using its process identifier (PID).

• killall nombre_proceso: Kill all processes with the same name. Be careful when using it, as it can stop important processes.

• nice: Adjusts the priority of a process. You can use it to change the priority of a process and give it more or less system resources.

• renice: Changes the priority of a running process. It is useful to adjust the priority of running processes in real time.