The primary distinction between top and htop is that top displays real-time data about system processes, whereas htop provides more interactivity and customization. htop allows users to sort and filter processes, view detailed information, and easily send signals to processes directly from the interface. While both tools show similar information, htop offers a more user-friendly and feature-rich experience for process monitoring.

The set -x command in a shell script is used to enable debugging mode for debugging purposes. When this mode is activated, the shell script will display each command before it is executed, making it useful for tracking the script's execution and finding errors.

To support both L2TP and IPsec in a VPN setup, you would likely consider using StrongSwan. StrongSwan is an open-source IPsec-based VPN solution that supports both L2TP and IPsec, providing secure and reliable VPN connectivity.

The /proc/cpuinfo file in the /proc directory is used to gather information about the system's CPU. It provides details about the processor, including its model, speed, and features. This is a valuable resource for understanding the CPU's capabilities and characteristics.

To ensure that filenames with spaces are treated as single arguments in a script, you should modify the OIFS (Original Internal Field Separator) variable. This allows you to temporarily change the IFS value to a specific character (e.g., newline) and then restore it to its original value after processing the filenames. This ensures that spaces don't break the filenames into multiple arguments.

The 'top' command is a Linux utility that allows you to monitor and manage system CPU performance. It provides a real-time view of system processes, CPU usage, memory usage, and more. You can use it to identify resource-intensive processes and manage system performance.

virt-manager is a graphical tool for managing virtual machines in Linux. It provides a user-friendly interface to create, configure, and manage virtual machines using various virtualization technologies, including KVM and QEMU.

A kernel that can have modules loaded and unloaded at runtime is referred to as a "modular" kernel. In a modular kernel, certain functionality can be added or removed via loadable kernel modules, making it more flexible and efficient.

The 'netstat' command provides information about network connections, routing tables, and network interface statistics. It's a powerful utility for diagnosing network-related issues and displaying network statistics and connections.

OpenVPN is considered highly secure and commonly used in Linux. It's an open-source VPN protocol that provides strong encryption and is widely trusted for creating secure network connections.