The gecos field, or
GECOS
General Comprehensive Operating System (GCOS, ; originally GECOS, General Electric Comprehensive Operating Supervisor) is a family of operating systems oriented toward the 36-bit GE/Honeywell mainframe computers.
The original version of GCOS wa ...
field is a field in each record in the
/etc/passwd
passwd is a command on Unix, Plan 9, Inferno, and most Unix-like operating systems used to change a user's password. The password entered by the user is run through a key derivation function to create a hashed version of the new password, wh ...
file on
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, an ...
and similar
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...
s. On UNIX, it is the 5th of 7 fields in a record.
It is typically used to record general information about the account or its user(s) such as their real name and phone number.
Format
The typical format for the GECOS field is a comma-delimited list with this order:
#User's
full name
A personal name, or full name, in onomastic terminology also known as prosoponym (from Ancient Greek πρόσωπον / ''prósōpon'' - person, and ὄνομα / ''onoma'' - name), is the set of names by which an individual person is known ...
(or application name, if the account is for a program)
#Building and room number or contact person
#Office
telephone number
A telephone number is a sequence of digits assigned to a landline telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices f ...
#Home telephone number
#Any other contact information (
pager
A pager (also known as a beeper or bleeper) is a wireless telecommunications device that receives and displays alphanumeric or voice messages. One-way pagers can only receive messages, while response pagers and two-way pagers can also acknow ...
number,
fax
Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...
, external e-mail address, etc.)
In most UNIX systems non-root users can change their own information using the ''chfn'' or ''chsh'' command.
History
Some early Unix systems at
Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984),
then AT&T Bell Laboratories (1984–1996)
and Bell Labs Innovations (1996–2007),
is an American industrial Research and development, research and scientific developm ...
used
GECOS
General Comprehensive Operating System (GCOS, ; originally GECOS, General Electric Comprehensive Operating Supervisor) is a family of operating systems oriented toward the 36-bit GE/Honeywell mainframe computers.
The original version of GCOS wa ...
machines for
print spooling and various other services, so this field was added to carry information on a user's GECOS identity.
Other uses
On
Internet Relay Chat
Internet Relay Chat (IRC) is a text-based chat system for instant messaging. IRC is designed for group communication in discussion forums, called '' channels'', but also allows one-on-one communication via private messages as well as chat an ...
(IRC), the real name field is sometimes referred to as the gecos field. IRC clients are required to supply this field when connecting.
Hexchat, an
X-Chat fork, defaults to 'realname', TalkSoup.app on
GNUstep
GNUstep is a free software implementation of the Cocoa (formerly OpenStep) Objective-C frameworks, widget toolkit, and application development tools for Unix-like operating systems and Microsoft Windows. It is part of the GNU Project.
GNUste ...
defaults to 'John Doe', and
irssi
Irssi ( ) is an IRC client program for Linux, FreeBSD, macOS and Microsoft Windows. It was originally written by Timo Sirainen, and released under the terms of the GNU GPL-2.0-or-later in January 1999.
Features
Irssi is written in the C progr ...
reads the operating system user's full name, replacing it with 'unknown' if not defined. Some IRC clients use this field for advertising; for example,
ZNC defaulted to "Got ZNC?", but changed it to "RealName = " to match its configuration syntax in 2015.
See also
*
General Comprehensive Operating System
General Comprehensive Operating System (GCOS, ; originally GECOS, General Electric Comprehensive Operating Supervisor) is a family of operating systems oriented toward the 36-bit GE/Honeywell mainframe computers.
The original version of GCOS wa ...
References
{{DEFAULTSORT:Gecos Field
Unix