CentOS View the system's last boot time and run time

1.uptime command

[Spark@master log_data]$ uptime
 09:18:01 up 20:17,  1 user,  load average:0.13, 0.12, 0.14

2. View/proc/uptime file Computing system startup time

[Spark@master log_data]$ cat/proc/uptime
73064.44 276161.85

Output: 73064.44 276161.85 The first number is the system has been running for 73064.44 seconds, using the System Tools date to calculate the system start time
Code:

[Spark@master log_data]$ date-d $ (awk-f. ' {print} '/proc/uptime ') second ago "+"%y-%m-%d%h:%m:%s "
2015-12-02 13: 00:59

3. View/proc/uptime files calculate system run time
Code:

[Spark@master log_data]$ cat/proc/uptime| Awk-f. ' {run_days=$1/86400;run_hour= (% 86400)/3600;run_minute= (% 3600)/60;run_second=$1% 60;printf ("system is running:%d days% D%d minutes, Run_days,run_hour,run_minute,run_second)} '
system is running: 0 days 20:19 26 seconds