groupadd/archive/2005

[[Category:Linux shell commands]] Techniques: Linux: groupadd

Text

Name

groupadd - Create a new group

Synopsis

standard: groupadd [-g gid [-o]]

group

Red Hat: groupadd [-g gid [-o]] [-r] [-f]

group

Description

The groupadd command creates a new group account using

the values specified on the command line and the default values from the system. The new group will be entered into the system files as needed. The options which apply to the groupadd command are

-g gid	The numerical value of the group's ID. This value must be unique, unless the -o option is used. The value must be non-negative. The default is to use the smallest ID value greater than 500 and greater than every other group. Values between 0 and 499 are typically reserved for system accounts.
Red Hat Linux only:
-r	This flag instructs groupadd to add a system account. The first available gid lower than 499 will be automatically selected unless the -g option is also given on the command line. This is an option added by Red Hat.
-f	This is the force flag. This will cause groupadd to exit with an error when the group about to be added already exists on the system. If that is the case, the group won't be altered (or added again). This option also modifies the way -g option works. When you request a gid that it is not unique and you don't specify the -o option too, the group creation will fall back to the standard behavior (adding a group as if neither -g or -o options were specified). This is an option added by Red Hat.

Files

• /etc/group - group account information
• /etc/gshadow - secure group account information

See Also

chfn(1), chsh(1), passwd(1), groups(1), groupdel(8), groupmod(8), useradd(8), userdel(8), usermod(8)

Author

Julianne Frances Haugh (jockgrrl@ix.netcom.com)

Notes

• This command is normally not on the search path for executables, so

you may need to use whereis to find it.

• This command usually requires root access.
• A system account is generally an account that isn't logged into

or used by users. Examples are audio, video, cdrom, dialout, scanner, staff, etc. It's not clear exactly what special handling these accounts may be receiving with Red Hat; see Questions. ==Examples== /usr/bin/groupadd newgrp

Questions

• What special handling do system accounts receive under Red Hat? (See

"notes" for known information about system accounts.)

• The action of the -r option ("add a system account") is a little

unclear -- does it create a system-type user account in addition to creating a group account? (And if so, what is the account's name?) Or is it merely adding a special system attribute to the group account created? If the latter, then the purpose of such accounts remains even less clear, as group accounts are by definition never logged into.

Edit Log

• 2005-06-09 Transcribed from Red Hat Linux 7.1 2.96-98 Linux

manpages and KUbuntu "hoary" (Debian 1:3.3.5-8ubuntu2) manpages.