Mac OS X in a Nutshell

Name

who

Synopsis

who [options] [file]

Displays information about the current status of the system. With no options, list the names of users currently logged in to the system. An optional system file (default is /var/run/utmp) can be supplied to give additional information. who is usually invoked without options, but useful options include am i and -u. For more examples, see cut, line, paste, tee, and wc.

Options

-H

Print headings.

-m

Report only about the current terminal.

-T

Report whether terminals are writable (+), not writable (-), or unknown (?).

-u

Report terminal usage (idle time). A dot (.) means less than one minute idle; old means more than 24 hours idle.

am i

Print the username of the invoking user. (Similar to results from id.)

Example

This sample output was produced at 8 a.m. on April 17:

% who -uH
NAME    LINE   TIME         IDLE   PID  COMMENTS
martha  ttyp3  Apr 16 08:14 16:25  2240   
george  ttyp0  Apr 17 07:33   .  15182

The output shows that the user martha has beenidle for 16 hours and 25 minutes (16:25, under the IDLE column).