了解MacBook自生产以来运行了多长时间

是否有可能找出自生产以来MacBook已开启多久？

有一个终端命令 ac

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.

当我在我的新机器上输入它时，它看起来是正确的，但是我9岁的Mac Pro为当前用户提供与总小时数相同的数字 - 这意味着它丢失了我的旧帐户[仍然活跃在那里但很少现在使用]自2008年以来已经存在。它只给出0小时。

如果没有人登录，它将无法计算机器可能已经打开的任何小时数。