What are the main interfaces provided by the Linux kernel for interaction with users and applications?

The Linux kernel provides several core interfaces for interaction with users and applications:

1. System Calls — the primary interface between user programs and the kernel. Through system calls, applications can request services from the kernel, such as file operations, processes, memory, and networking.

2. /proc and /sys Filesystems — virtual filesystems through which information about the system state can be obtained and some kernel parameters can be managed.

3. Devices in /dev — interfaces to hardware devices and drivers, through which applications can interact with hardware.

4. Sockets and IPC (Inter-Process Communication) — mechanisms for data exchange between processes.

Thus, the main interface is a set of system calls that implement interaction between applications and kernel resources and services.