topic Re: while true loop in Operating System - HP-UX

while true loop

Norman_21 — Thu, 03 Oct 2002 03:14:33 GMT

hi guys,

I've written the following script to cancel a printer jobs queue but the script keeps prompting asking for an input again:

while true
do
echo "enter printer name ?\c"
read ANSW
cancel -e $ANSW
done

appreciate you advise and support..

Re: while true loop

Patrick Wallek — Thu, 03 Oct 2002 03:19:09 GMT

Yeah, that's what the while-true construct does.

To get out of that loop you'll have to do a CTRL-C

What exactly do you want the script to do? Do you want it to execute once? Do you want it to prompt the user before it executes again?

We need more info before we can effectively help you.

Re: while true loop

Balaji N — Thu, 03 Oct 2002 03:33:17 GMT

Hi,
The read statement is inside the while loop and hence as long as the while loop is true, it will prompt you for the input. Take the read statement out of the while loop.

BTW, what exactly are you trying. If you just need to cancel the jobs of a specific printer, just take away the loop and execute the rest of the commands.

Regards
Balajio

Re: while true loop

Balaji N — Thu, 03 Oct 2002 03:34:32 GMT

Re: while true loop

Patrick Chim — Thu, 03 Oct 2002 03:42:02 GMT

Hi,

You can modify your script like this,

while true
do
echo "enter printer name ?\c"
read ANSW
if [ x"$ANSW" = "x" ]
then
echo "program exit"
exit
fi
cancel -e $ANSW
done

If you just press "enter" at the question, the program will quit !!

Regards,
Patrick

Re: while true loop

S.K. Chan — Thu, 03 Oct 2002 03:46:30 GMT

If you want to cancel everything in all of the printer queue you can do this ..

for printername in $(lpstat|grep \^printer|awk '{print $4}')
do
cancel -e $printername
done

This command extract all the printername configured in your system.
$ lpstat|grep \^printer|awk '{print $4}'

Not sure if this is what you want.

Re: while true loop

Norman_21 — Thu, 03 Oct 2002 07:26:19 GMT

Hi guys,

I realy appreciate your prompt reply. However, I was not sure if I removed the loop
the script will cancel the whole bunch of a specific printer jobs. I'll try and see what happens?

Re: while true loop

Balaji N — Thu, 03 Oct 2002 08:19:07 GMT

Hi,
From the man pages of cancel.

-e Empty the spool queue of all requests for each printer.
Only users with appropriate privileges can use this
option.

So, if ur root and run cancel -e , it will cancel all requests.

HTH
-balaji

Re: while true loop

Norman_21 — Thu, 24 Feb 2005 12:57:11 GMT

Closed...