Giving "read" from standard input a timeout.

rello · #1 (**permalink**) 03-02-2005

I want to prompt a user for input but I want it to timeout after a specified time if no response is given. I tried the sleep command but this does not work. I am using ksh.
Thanks.

vgersh99 · #2 (**permalink**) 03-02-2005

Quote:

Originally Posted by rello

I want to prompt a user for input but I want it to timeout after a specified time if no response is given. I tried the sleep command but this does not work. I am using ksh.
Thanks.

Code:

#!/bin/sh
#
STTY=`stty -g`
WAIT=60
printf 'enter [y/n] '
stty intr '' -icanon min 0 time $WAIT ignbrk -brkint -ixon isig
read ans
stty $STTY
case ${ans:=y} in [yY]*) ;; *) exit ;; esac
echo do the rest
exit

or read timeout

muthukumar · #3 (**permalink**) 03-03-2005

You can use read timeout functionality to do this. We can make your requirement as,

Code:

#!/bin/sh
# input timeout

echo "Enter your input"
read -t 5 input
if [[ $? -ne 0 ]]
then
  echo "User did not enter any input"
  exit 1
else
  echo "User did input as $input"
fi

exit 0
# END #

Try this in bash.

HTH.

vigsgb · #4 (**permalink**) 07-07-2005

[QUOTE=vgersh99]

Code:

#!/bin/sh
#
STTY=`stty -g`
WAIT=60
printf 'enter [y/n] '
stty intr '' -icanon min 0 time $WAIT ignbrk -brkint -ixon isig
read ans
stty $STTY
case ${ans:=y} in [yY]*) ;; *) exit ;; esac
echo do the rest
exit

[QUOTE]

I am on an IBM p570 with AIX 5.3 and when for some reason I can only get a time delay of 20 seconds. If I use WAIT=200 I get twenty seconds as would be expected, however when I use WAIT=300 I get 4 seconds. Can anyone explain this to me?

Thanks

r2007 · #5 (**permalink**) 07-07-2005

Quote:

I am on an IBM p570 with AIX 5.3 and when for some reason I can only get a time delay of 20 seconds. If I use WAIT=200 I get twenty seconds as would be expected, however when I use WAIT=300 I get 4 seconds. Can anyone explain this to me?

Just guess
WAIT=200 means 200/10=20 seconds
WAIT=300 means (300 mod 256)/10=4.5 secondes

vigsgb · #6 (**permalink**) 07-08-2005

Quote:

Originally Posted by r2007

Just guess
WAIT=200 means 200/10=20 seconds
WAIT=300 means (300 mod 256)/10=4.5 secondes

That seems to be correct as 256 gives a zero wait time. How did you come up with that? or What is the logic behind the calculaton?

rello · #7 (**permalink**) 03-03-2005

Thank you both for your help. I am still having trouble since neither works with ksh.
I have tried modifying both and still am not having much luck.

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