Very Computer

hello,
Can anybody tell me ,if there is any way to restrict the user to enter only
one character as input. i.e. if I do
    read var
it will read a full word.But I want that the user is not allowed to enter
more than
one character.

Also is it possible to accept any input without pressing <Enter>.

with regards
sachin

Quote:> hello,
> Can anybody tell me ,if there is any way to restrict the user to enter
only
> one character as input. i.e. if I do
>     read var
> it will read a full word.But I want that the user is not allowed to enter
> more than
> one character.

> Also is it possible to accept any input without pressing <Enter>.

> with regards

Sachin,

Neither of the above tasks can be performed very 'neatly' within a shell
script.

The following script, based on an example in the comp.unix.shell FAQ,
accomplishes both tasks:

#!/bin/sh

echo -n "Enter a character: "
stty cbreak         # or  stty raw
readchar=`dd if=/dev/tty bs=1 count=1 2>/dev/null`
stty -cbreak

echo
echo "You typed in: $readchar"

As you can see, however, it is not a totally 'clean' solution, but it *does*
work.

I hope this helps.

On Tue, 17 Apr 2001 00:45:56 +1000, "Anthony Borla"

Yup.
Using ksh93 the timed read -t option can do this elegantly.
A typeset limits input to one char and can force case and left align
in case of dribble on the space bar.
see www.kornshell.com to get opensource ksh93 from AT&T.
 (thanks guys, much appreciated)

Something like this should do what you want with ksh built ins.
Not tested as I am on a dos box at present. so  RTFM

#!/usr/bin/ksh
typeset -Ll1 input_char

read -t2 input_char
print "you entered $input_char"

cheers
Roger D

I don't think it can.  Read requires a line end delimiter to be received
before it will set the variable:

   $ echo $0
   ksh93
   $ print "c" | read -t1 x
   $ echo $x
   c
   $ print -n "c" | read -t1 x
   $ echo $x

   $ print -n "b:" | read -t1 -d: x
   $ echo $x
   b
   $

So although the read will timeout,  the character will not be read.
With ksh93,  you still need stty and dd.

--
Dan Mercer

Quote:> A typeset limits input to one char and can force case and left align
> in case of dribble on the space bar.
> see www.kornshell.com to get opensource ksh93 from AT&T.
>  (thanks guys, much appreciated)

> Something like this should do what you want with ksh built ins.
> Not tested as I am on a dos box at present. so  RTFM

> #!/usr/bin/ksh
> typeset -Ll1 input_char

> read -t2 input_char
> print "you entered $input_char"

> cheers
> Roger D

Opinions expressed herein are my own and may not represent those of my employer.