I am running a number of processes through a kill -15 loop as a temporary fix to some viscious memory leaks. I cannot pass the entire list of processes through the kill at once, because the nature of the monitoring my client has will cause the software to failover.

Because of the large number of processes a

kill -15 $l
sleep 1

is still taking too long. How can I sleep for less than this?

Technically, sleep 0 is the answer although that is probably not what you are looking for.

I doubt the sleep is your real problem - you start the kill, and after it is done, you sleep for one second. You state "How can I get a command to sleep < 1 second" You can't. You can't get any command to sleep...you are not putting the command to sleep, you are putting your process to sleep for that amount of time. If you are looking to wait until the kill is completed, or looking to continue before it is completed, the sleep command is not what you want. The sleep command is to waste time until another check can be done while we are waiting for something to happen. If you need to wait less than a second, leave the sleep out.

Please give greater detail on what you are attempting to accomplish. And of course, your real fix is to get rid of the problem with memory, not write a script to kill off processes (IMO).