Unknown option: "-8" Unix manual page for ac. (host=minya system=Darwin)
AC(8)                     BSD System Manager's Manual                    AC(8)

NAME
     ac -- display connect-time accounting

SYNOPSIS
     ac [-d] [-p] [-w file] [users ...]

DESCRIPTION
     A record of individual login and logout times are written to the system
     log by login(8) and launchd(8), respectively.  The program ac examines
     these records and writes the accumulated connect time (in decimal hours)
     for all logins to the standard output.

     Options available:

     -d      Display the connect times in 24 hour chunks.

     -p      Display individual user totals.

     -w file
             Read raw connect time data from file, instead of the system log.

     users ...
             Display totals for the given individuals only.

     If no arguments are given, ac displays the total amount of login time for
     all active accounts on the system.

SEE ALSO
     login(1), utmpx(5), launchd(8), sa(8)

HISTORY
     An ac command appeared in Version 6 AT&T UNIX.

4th Berkeley Distribution       April 19, 1994       4th Berkeley Distribution