Explain the purpose and structure of the /proc directories in a Linux system.

/proc is a virtual filesystem in Linux that provides an interface to kernel data and system process information. It does not store real files on disk but displays current system states and parameters as files and directories.

Main features and structure:

• At the root /proc, there are files and directories with system information, for example:

  • /proc/cpuinfo — information about the processor
  • /proc/meminfo — information about memory
  • /proc/uptime — system uptime

• For each running process, there is a directory named after its PID, for example /proc/1234. Inside, there are files with process information:

  • cmdline — launch command
  • status — process status
  • fd/ — links to open file descriptors

• /proc is used for system monitoring and configuration, as well as for diagnostic information.

Example: to find out the number of processors, you can read the /proc/cpuinfo file or look at the number of directories with numeric names corresponding to processes.