2 sleep - suspend operation for a specified time
8 n non-negative real, defaults to 1
10 return integer or null value
13 This uses the C-library sleep (if n is integral) or usleep (for
14 non-integral n) to suspend operation for n seconds. If n is an
15 integer and the sleep is stopped by an interruption, the number
16 of seconds remaining is returned.
18 One kind of use is to slow down output to permit easier reading of
21 > for (i = 0; i < 100; i++) {
26 The following illustrates what happens if ctrl-C is hit 5 seconds
27 after the first command: