containing a summary of how the kernel is managing its memory. , one of the most important files in , containing a list of the kernel modules currently loaded . It gives some indication (not always entirely correct) of dependencies. , a symlink to self/mounts which contains a list of the currently mounted devices and their mount points (and which file system is in use and what mount options are in use). , a directory containing useful information about the network stack, in particular , which lists existing network connections (particularly useful for tracking routing when iptables FORWARD is used to redirect network connections) , a list of the device-numbers, their size and names which the kernel has identified as existing partitions , giving information about any devices connected via a SCSI or RAID controller a symbolic link to the current (traversing) process at (i.e. where PID is that of the current process). , listing statistics on the caches for frequently-used objects in the Linux kernel , a list of the active swap partitions, their various sizes and priorities Access to dynamically configurable kernel options under . Under appear directories representing the areas of kernel, containing readable and writable virtual files. For example, a commonly referenced virtual file is , because it is necessary for routing firewalls or tunnels. The file contains either a '1' or a '0': if it is 1, the IPv4 stack forwards packets not meant for the local host, if it is 0 then it does not. , containing memory-sharing and inter-process communication (IPC) information. , containing information about the current terminals; looks to be a list of the different types of tty available - each of which is a list of those of each type , the length of time the kernel has been running since boot and spent in idle mode (both in seconds) , containing the Linux kernel version, distribution number, gcc version number (used to build the kernel) and any other pertinent information relating to the version of the kernel currently running other files depending on various hardware, module configurations, and changes to the kernel. The basic utilities that use /proc under Linux come in the procps ( processes) package, and only function in conjunction with a mounted . CYGWIN Cygwin implemented a procfs that is basically the same as the Linux procfs. References Sources Unix 8th Edition proc(2) manual page -