<sleep $seconds [wake]>
sleep function pauses (sleeps) for
seconds (for each value of
sleep returns the number of seconds remaining to be slept (a
float), which is normally 0. However, if the "
sleep may wake up early and return a non-zero value,
if a signal was caught. (This can be used to wait for another process
to signal the script and wake it up.)
sleep function was added Sep. 17 1996. The
flag was added Sep. 1 2000; previous versions behaved as if it were
Sleep durations with fractions of a second may be given, e.g. 1.5. However, the actual sleep duration may vary depending on the platform's clock resolution.