Printing current time in milliseconds or nanoseconds with printf builtin

Question

We can print the current time with the builtin printf function, without needing to invoke an external command like date, like this:

Answer 1

In bash 5, you can get microsecond precision from EPOCHREALTIME. However, printf itself has no way to access that directly, so you need to extract the microseconds yourself.

$ echo $EPOCHREALTIME; printf '%(%F:%T)T.%d\n' "$EPOCHSECONDS" "${EPOCHREALTIME#*.}"; echo $EPOCHREALTIME
1554006709.936990
2019-03-31:00:31:49.937048
1554006709.937083

This takes a little time, but the result appears to be accurate to about 0.05 milliseconds.