PROC(5) Linux Programmer's Manual PROC(5)
proc - process information pseudo-file system
The proc file system is a pseudo-file system which is used as an interface to kernel data structures. It is commonly mounted at /proc.
Most of it is read-only, but some files allow kernel variables to be changed.
The following outline gives a quick tour through the /proc hierarchy.
There is a numerical subdirectory for each running process; the subdirectory is named by the process ID. Each such subdirectory
contains the following pseudo-files and directories.
/proc/[pid]/auxv (since 2.6.0-test7)
This contains the contents of the ELF interpreter information passed to the process at exec time. The format is one unsigned long
ID plus one unsigned long value for each entry. The last entry contains two zeros.
/proc/[pid]/cgroup (since Linux 2.6.24)
This file describes control groups to which the process/task belongs. For each cgroup hierarchy there is one entry containing
colon-separated fields of the form:
The colon-separated fields are, from left to right:
1. hierarchy ID number
2. set of subsystems bound to the hierarchy
3. control group in the hierarchy to which the process belongs
This file is only present if the CONFIG_CGROUPS kernel configuration option is enabled.
This holds the complete command line for the process, unless the process is a zombie. In the latter case, there is nothing in this
file: that is, a read on this file will return 0 characters. The command-line arguments appear in this file as a set of strings
separated by null bytes ('