Operate running systems

Marcos is studying for his RHCE exam. Please generate and explain examples and commands to help him to master this objective: Operate running systems.

Certainly! Operating running systems is a key objective in the RHCE (Red Hat Certified Engineer) exam. Let's explore some examples and commands to help Marcos master this objective.

1. Process Management:

• Example: Checking running processes and their resource utilization using the top command:

  top

  Explanation: The top command provides real-time information about system processes, CPU usage, memory usage, and other system statistics. It allows you to monitor and manage processes interactively.

• Example: Terminating a running process using the kill command:

  kill <PID>

  Explanation: The kill command sends a signal to a process specified by its process ID (PID) to terminate it. The default signal sent is SIGTERM, but you can specify a different signal if needed.

2. System and Service Management:

• Example: Starting, stopping, and restarting a service using the systemctl command:

  sudo systemctl start <service-name>

  sudo systemctl stop <service-name>

  sudo systemctl restart <service-name>

  Explanation: The systemctl command is used to manage system services. These commands start, stop, or restart a service specified by its service name. You may need to run the commands with superuser privileges (sudo).

• Example: Enabling a service to start at boot using the systemctl command:

  sudo systemctl enable <service-name>

  Explanation: The enable option configures a service to start automatically at system boot. This ensures that the service starts up after a reboot or system restart.

3. Network Configuration:

• Example: Configuring network interfaces using the nmcli command:

  nmcli connection modify <interface-name> ipv4.method manual ipv4.addresses <IP>/<subnet>

  nmcli connection up <interface-name>

  Explanation: The nmcli command-line tool allows you to manage network connections. The first command configures a network interface with a static IPv4 address. The second command brings up the specified network interface.

• Example: Displaying network configuration using the ip command:

  ip address show

  ip route show

  Explanation: The ip command provides information about network interfaces, IP addresses assigned to them, and routing tables. The address show subcommand displays IP address details, while the route show subcommand shows the system's routing table.

These examples cover some essential commands for operating running systems, including process management, system and service management, and network configuration. By practicing these commands and understanding their usage, Marcos can effectively operate and manage Linux systems during his RHCE exam.