得之我幸 失之我命

when someone abandons you，it is him that gets loss because he lost someone who truly loves him but you just lost one who doesn’t love you.

| system

系统开机时间和重启记录

在 linux 系统上查看系统开机时间和重启记录，在排除 case 中连接 ssh 挂掉的原因中，这也是一个方向，这里记录 7 种方法

  1. who -b
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$ who -b  # time of last system boot，查看最后一次（上次）系统启动的时间
system boot  2020-12-21 17:10
  1. who -r
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$ who -r  # print current runlevel，同时也会输出系统启动时间
run-level 5  2020-08-28 04:57
  1. last reboot
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$ last reboot -f /var/log/wtmp.1  # 之所以需要 -f 是因为我要查看的是 2020 年的重启记录，而现在正好 2021 年初，新的记录文件中无法查询到
reboot   system boot  5.4.0-58-generic Mon Dec 21 17:10   still running
reboot   system boot  5.4.0-58-generic Mon Dec 21 15:37   still running
reboot   system boot  5.4.0-58-generic Mon Dec 21 15:23   still running
reboot   system boot  5.4.0-58-generic Fri Dec 18 13:54   still running

wtmp.1 begins Wed Dec  2 16:07:27 2020
  1. top
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$ top  # up 后表示系统到目前运行了多久时间，所以可以反过来推算系统重启时间
top - 13:35:55 up 13 days, 20:25,  1 user,  load average: 0.00, 0.00, 0.00
Tasks: 178 total,   1 running, 138 sleeping,   0 stopped,   0 zombie
%Cpu(s):  1.8 us,  0.7 sy,  0.0 ni, 97.4 id,  0.2 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem :  1980840 total,   154820 free,   328376 used,  1497644 buff/cache
KiB Swap:  2097148 total,  2025980 free,    71168 used.  1461096 avail Mem

PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
  1. w
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$ w  # show who is logged on and what they are doing，up 后表示系统到目前运行了多久时间，所以可以反过来推算系统重启时间
13:36:20 up 13 days, 20:26,  1 user,  load average: 0.00, 0.00, 0.00
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
test     pts/0    10.140.14.68     13:14    4.00s  0.06s  0.00s w
  1. uptime
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$ uptime  # tell how long the system has been running，up 后表示系统到目前运行了多久时间
13:36:54 up 13 days, 20:26,  1 user,  load average: 0.00, 0.00, 0.00
  1. 借助 /proc/uptime
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$ date -d "`cut -f1 -d. /proc/uptime` seconds ago"
2020年 12月 21日 星期一 17:10:11 CST

$ date -d "$(awk -F. '{print $1}' /proc/uptime) second ago" +"%Y-%m-%d %H:%M:%S"
2020-12-21 17:10:11

be yourself, everyone else is already taken.

ESC