1.uptime命令
uptime gives a one line display of the following information. The current 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.
uptime
输出:
16:11:40 up 59 days, 4:21, 2 users, load average: 0.00, 0.01, 0.00
2.查看/proc/uptime文件计算系统启动时间和运行时间
/proc/uptime
This file contains two numbers: the uptime of the system (seconds), and the amount of time spent in idle process (seconds).
cat /proc/uptime输出:
5113396.94 575949.85第一数字即是系统已运行的时间5113396.94 秒，运用系统工具date即可算出系统启动时间：
date -d "$(awk -F. '{print $1}' /proc/uptime) second ago" +"%Y-%m-%d %H:%M:%S"输出:
2008-11-09 11:50:31
还可算出系统运行总时间:
cat /proc/uptime| awk -F. '{run_days=$1 / 86400;run_hour=($1 % 86400)/3600;run_minute=($1 % 3600)/60;run_second=$1 % 60;printf("系统已运行：%d天%d时%d分%d秒",run_days,run_hour,run_minute,run_second)}'
输出:
系统已运行：59天4时13分9秒
转载：http://www.cnblogs.com/xd502djj/archive/2011/05/03/2035599.html