Alpine Linux

It appears that busybox beep does not implement delay. Or it doesn't implement it properly.

1. -d switch should allow definition of delay in ms, which applies between each beep (not after the last one)
2. When -d is not specified, there should be a default delay of 100 ms.

Proof: the following two commands do the same thing:

• # /bin/busybox beep -d 1000 -f 1000 -r 2
• # /bin/busybox beep -f 1000 -r 2

Tested against busybox-1.15.3-r1