What is inside the Linux directory: /proc?

A virtual file system containing information about processes and kernel resources of the operating system in real-time.

Examples of contents:

• Process information: /proc/PID/ (where PID is the process identifier) contains files with details about a specific process (e.g., /proc/1234/cmdline - command line, /proc/1234/status - process status).
• System information: /proc/cpuinfo, /proc/meminfo, /proc/filesystems, /proc/version contain data about the processor, memory, file systems, and kernel version.
• Kernel parameters: /proc/sys/ provides access to kernel settings that can be read and modified "on the fly".

Example of accessing information:

# View memory information
cat /proc/meminfo

# View command line of process with PID 1234
cat /proc/1234/cmdline

/proc does not store data on disk but generates it dynamically upon access. This is useful for system monitoring and diagnostics.