procfs (or the proc filesystem) is a special filesystem in UNIX-like operating systems that presents information about processes and other system information in a hierarchical file-like structure
The proc filesystem is a filesystem that presents information about running processes. It is available under many Unix variants including Solaris, Linux and AIX, but is absent not most BSD variants. On Linux, the proc filesystem exposes other system data as well.
The proc filesystem is normally mounted at
/proc, and information about a process is presented in a file or directory named after the process ID, e.g.
/proc/123 presents information about process 123.