[unix] Get Current date in epoch from Unix shell script

How to get the current date value in epoch i.e., number of days elapsed since 1970-1-1. I need solution in unix shell script.

echo `date +%s`/86400 | bc

Depending on the language you're using it's going to be something simple like

CInt(CDate("1970-1-1") - CDate(Today()))

Ironically enough, yesterday was day 40,000 if you use 1/1/1900 as "day zero" like many computer systems use.

echo $(($(date +%s) / 60 / 60 / 24))

The Unix Date command will display in epoch time

the command is

date +"%s"

https://linux.die.net/man/1/date

Edit: Some people have observed you asked for days, so it's the result of that command divided by 86,400