Shell Programming and Scripting

Greetings.

I've been wondering about this one for some time: Is there an alternative to sleep in bash?

The reason: I'd like to simply limit the amount of processor usage in continuous while : script scenarios without spawning endless sleep processes as well. After beating the manpages, I still haven't a clue as to how one might do something like this...

Any ideas? Is it even possible???

Running 'Buntu 12.04, BTW


Thanks!

Why is a problem. You could try using the subsystem or .

Switch to ksh:

Code:

$ ksh
$ whence -v sleep
sleep is a shell builtin
$

Or maybe this...

Code:

#! /bin/bash
mkfifo myfifo 2>/dev/null
n=0
cat myfifo | while : ; do
        ((n=n+1))
        read -t 2 junk
        echo loop $n
done

As used in the AudioScope.sh project:-

Code:

delay()
{
	read -n1 -s -t$1
}

Called as delay <time_in_seconds> and has the advantage of keyboard override...

However, it requires a tty. Not gonna fly in a cron job or even a background process.

Thanks for the feedback, folks.

However, "read" will not work from an actual script context in Xubuntu 12.04. The "while" simply blows past it; and this comes out every time:

"illegal option -t"



Of course, it'll run just fine directly from the terminal or in any context on Parted Magic...

Anything else to play with out there which has a timeout that might be usable???


Thanks Again!

I guess you have an older bash then. Your only options are to switch to a language with more power or just live with the sleep processes. The sleep processes would not bother me and I don't know why you worry about them.

So ksh, newer bash, or something like perl would all do what you want.