Get seconds since Epoch in Bash

bash 5.0 natively supports retrieving seconds since Epoch using a variable.

Native bash method

1echo $EPOCHSECONDS # 1682740449

If seconds are preferred:

1echo $EPOCHREALTIME # 1682740449.252199

If milliseconds are preferred:

1echo $(( ${EPOCHREALTIME/./} / 1000 )) # 1682740449252

Using date

In addition to using the native bash method, date may be used.

According to the date manual:

%s seconds since the Epoch (1970-01-01 00:00 UTC)

1echo $(date +%s) # 1682740326

If milliseconds seconds are preferred:

1echo $(date +%s%3N) # 1682740449252