用途
man page
uptime gives a one line display of the following information. The cur‐ rent time, how long the system has been running, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.
System load averages is the average number of processes that are either in a runnable or uninterruptable state. A process in a runnable state is either using the CPU or waiting to use the CPU. A process in unin‐ terruptable state is waiting for some I/O access, eg waiting for disk. The averages are taken over the three time intervals. Load averages are not normalized for the number of CPUs in a system, so a load aver‐ age of 1 means a single CPU system is loaded all the time while on a 4 CPU system it means it was idle 75% of the time.
Load averages are not normalized for the number of CPUs in a system, so a load aver‐ age of 1 means a single CPU system is loaded all the time while on a 4 CPU system it means it was idle 75% of the time.
语法
$ uptime
10:14:31 up 10 days, 20:55, 6 users, load average: 0.28, 0.42, 0.54
上面的结果显示的分别是系统的当前时间，运行时间，当前用户数，过去1, 5, 15分钟的系统平均负载 总体来说，值为1时，当只有单个CPU表示已经完全利用，当有４个CPU时，表示还有75%的空闲.
关于平均负载的值可以阅读
http://blog.scoutapp.com/articles/2009/07/31/understanding-load-averages