What is proc?

The /proc filesystem is a virtual filesystem in Linux and other Unix-like operating systems that presents information about running processes and the kernel. It provides a hierarchical view of system data, accessible as files and directories, even though these files don't actually exist on a physical storage device. Instead, they are dynamically created by the kernel when accessed.

Here's a breakdown of important aspects:

• Process Information: Each running process has a directory named after its process ID (PID) under /proc. For example, the process with PID 123 would have a directory /proc/123. These directories contain various files providing information about the process, such as its memory usage, open files, command line arguments, and execution status.

• Kernel Information: /proc also holds information about the kernel itself. Files like /proc/version and /proc/uptime provide details about the kernel version and how long the system has been running. Other important files include /proc/meminfo (memory statistics), /proc/cpuinfo (CPU information), and /proc/interrupts (interrupt usage).

• Dynamic Nature: The files and directories within /proc are not static. They are generated on-the-fly when they are read. This ensures that the information is always up-to-date.

• Uses: /proc is used by various system monitoring and diagnostic tools like ps, top, vmstat, and lsof. It provides a standardized and easily accessible way for these tools to gather system information.

• Security: Access to files in /proc is controlled by standard file permissions. Some files are only readable by the root user, while others are accessible to all users. Some files are read-only, while others can be written to in order to adjust kernel settings (requires appropriate permissions).

Key Concepts and Files (with links):

• Process ID (PID)
• /proc/version
• /proc/uptime
• /proc/meminfo
• /proc/cpuinfo
• /proc/interrupts

In summary, /proc is a vital pseudo-filesystem that offers a real-time window into the inner workings of a Linux system, enabling system administrators, developers, and monitoring tools to observe and interact with processes and the kernel.