/proc File System

The /proc file system enables running processes to be accessed and manipulated as files by the system calls open, close, read, write, lseek, and ioctl. While the /proc file system is most useful for debuggers, it enables any process with the correct permissions to control another running process. Thus, a parent/child relationship does not have to exist between a debugger and the process being debugged. The dbx debugger that ships in Digital UNIX Version 4.0 supports attaching to running processes through /proc. For more information, see the proc(4) and dbx(1) reference pages.