finger either displays information about which users are currently using the system or displays information about a specific user.
There are two basic usages. Without a name argument, information about all currently logged-in users is displayed. With one or more name specified, finger displays information about people known to the system and matching those names. The default output format is to display a one-line summary about the most recent login(s) of people (one for each person). This gives enough information to quickly determine if somebody is currently on the system and where to reach him/her.
If name is of the form name@host finger makes a connection to host and performs the same operation as in the local case. The remote site must run a finger server and the output entirely depends on the configuration of the remote host.
Several special actions by finger can be invoked by specifying one of the following strings for name. If a remote host is fingered, these actions may not be available or produce another result.
To change what is displayed if someone requests information about you, edit the file .fingerconf by using either a text editor or pfinger See fingerconf(5) for a description of the file format.
Put a public key in the file .key If it is a PGP public key put it in .pgpkey When someone fingers you a line will be displayed that indicates the existence of the file and how to receive it.
If you make plans (e.g. You are in holidays for some weeks) edit the file .plan This file is automatically displayed if someone fingers you. Therefore note: Do not put public keys in the plan-file. It only messes the display up.
If your system does not run the pfinger daeomon, the file .fingerconf cannot be used. In this case your personal information is read from the system's password file. Use chfn(1) to change that information.