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Alternative to Sleep?


 
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# 1  
Old 03-12-2014
Alternative to Sleep?

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 Smilie


Thanks!
# 2  
Old 03-12-2014
Why is
Quote:
sleep
a problem. You could try using the
Quote:
at
subsystem or
Quote:
cron
.
# 3  
Old 03-12-2014
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

Smilie
This User Gave Thanks to Perderabo For This Post:
# 4  
Old 03-12-2014
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...
# 5  
Old 03-12-2014
Quote:
Originally Posted by wisecracker
has the advantage of keyboard override...
However, it requires a tty. Not gonna fly in a cron job or even a background process.
This User Gave Thanks to Perderabo For This Post:
# 6  
Old 03-12-2014
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"

Smilie

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!
# 7  
Old 03-12-2014
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.

Last edited by Perderabo; 03-13-2014 at 08:29 AM..

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