BUP-TICK()

bup-tick - wait for up to one secondbup tickbup tick waits until time(2) returns a different value than it originally did. Since time() has a granularity of one second, this can cause a delay of up to one second.

This program is useful for writing tests that need to ensure a file date will be seen as modified. It is slightly better than sleep(1) since it sometimes waits for less than one second.
$ date; bup tick; date
Sat Feb  6 16:59:58 EST 2010
Sat Feb  6 16:59:59 EST 2010
Part of the bup(1) suite.