Man page 1 : chfn

chfn - change real user name and information

chfn [-f full_name] [-r room_no] [-w work_ph] [-h home_ph] [-o other] [user]

The chfn command changes user fullname, office number, office extension, and home phone number information for a user\*(Aqs account. This information is typically printed by finger(1) and similar programs. A normal user may only change the fields for her own account, subject to the restrictions in /etc/login.defs. (The default configuration is to prevent users from changing their fullname.) The superuser may change any field for any account. Additionally, only the superuser may use the -o option to change the undefined portions of the GECOS field.

These fields must not contain any colons. Except for the other field, they should not contain any comma or equal sign. It is also recommended to avoid non-US-ASCII characters, but this is only enforced for the phone numbers. The other field is used to store accounting information used by other applications.

If none of the options are selected, chfn operates in an interactive fashion, prompting the user with the current values for all of the fields. Enter the new value to change the field, or leave the line blank to use the current value. The current value is displayed between a pair of [ ] marks. Without options, chfn prompts for the current user account.

The following configuration variables in /etc/login.defs change the behavior of this tool:

CHFN_RESTRICT (string)
    This parameter specifies which values in the gecos field of the /etc/passwd file may be changed by regular users using the chfn program. It can be any combination of letters f, r, w, h, for Full name, Room number, Work phone, and Home phone, respectively. For backward compatibility, yes is equivalent to rwh and no is equivalent to frwh. If not specified, only the superuser can make any changes. The most restrictive setting is better achieved by not installing chfn SUID.

/etc/login.defs
    Shadow password suite configuration.

/etc/passwd
    User account information.

chsh(1), login.defs(5), passwd(5).