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bashtimemilliseconds

bash, get current time in milliseconds since midnight

Is there a way to get the current milliseconds past midnight in bash? And if there is a way to do it entirely in bash, how good or bad is the precision of that timestamp?

Solution

  • You can get today's midnight with:

    date -d 'today 00:00:00'

    in UNIX stamp:

    date -d 'today 00:00:00' "+%s"

    So if you want to get the difference, do:

    midnight=$(date -d 'today 00:00:00' "+%s")
now=$(date "+%s")
diff_mills=$(( ($now - $midnight) * 1000 ))

    as %s indicates seconds, we have to *1000 to get milliseconds.

    With %N (nanoseconds):

    midnight=$(date -d 'today 00:00:00' "+%s.%N")
now=$(date "+%s.%N")
diff_mills=$(echo "( $now - $midnight ) * 1000" | bc)