The who -b command desn't show me the last reboot times on my Raspberry 3
:~ $ uname -a
Linux xxxxx 4.9.35-v7+ #1014 SMP Fri Jun 30 14:47:43 BST 2017 armv7l GNU/Linux
:~ $ who -b
system boot 1970-01-01 01:00
I configured the ntp daemon as the date is uptodate.
How to configure the system for getting this king of information.
Regards,
Short answer: Use: uptime --since (-s for short)
You can use the uptime command to find out how long it has been since the Pi (or any Unix/Linux OS) has booted. The -s flag tells uptime to calculate the boot time.
The Pi doesn't have a real-time clock (though there are RTC chips that you can add). This means it does not know the date/time as it boots. If it has access to a network, it'll reach out to a time-server to set these. But if it doesn't have a network, it will rely on a fake hardware clock (basically a file where it periodically writes the time). It isn't accurate, but at least it fixes problems where log files have "newer" entries with older date/time stamps than "older" entries.
See also.
