coreutils: uptime invocation

1 
1 21.7 ‘uptime’: Print system uptime and load
1 ===========================================
1 
1 ‘uptime’ prints the current time, the system’s uptime, the number of
1 logged-in users and the current load average.
1 
1    If an argument is specified, it is used as the file to be read to
1 discover how many users are logged in.  If no argument is specified, a
1 system default is used (‘uptime --help’ indicates the default setting).
1 
11    The only options are ‘--help’ and ‘--version’.  ⇒Common
 options.
1 
1    For example, here’s what it prints right now on one system I use:
1 
1      $ uptime
1       14:07  up   3:35,  3 users,  load average: 1.39, 1.15, 1.04
1 
1    The precise method of calculation of load average varies somewhat
1 between systems.  Some systems calculate it as the average number of
1 runnable processes over the last 1, 5 and 15 minutes, but some systems
1 also include processes in the uninterruptible sleep state (that is,
1 those processes which are waiting for disk I/O). The Linux kernel
1 includes uninterruptible processes.
1 
1    ‘uptime’ is installed only on platforms with infrastructure for
1 obtaining the boot time, and other packages also supply an ‘uptime’
1 command, so portable scripts should not rely on its existence or on the
1 exact behavior documented above.
1 
1    An exit status of zero indicates success, and a nonzero value
1 indicates failure.
1