Explain the concept of a container in Linux and its main features.

A container in Linux is an isolated environment that allows running applications with their own dependencies and configurations without affecting the rest of the system. Key features of containers:

• Process and filesystem isolation using namespaces and cgroups.
• Lightweight compared to virtual machines, as containers use the host system's kernel.
• Fast startup and scaling.
• Ability to package an application with its environment for portability.

Example: Docker — a popular tool for creating and managing containers in Linux.