Shell Programming and Scripting

Hello All,

In ksh I am trying to ensure that user inputs are integers otherwise redisplay prompt with the following code;

Code:

a=0
b=0
c=0

read b?"Please enter a number: "
read c?"Please enter another number: "
while [ $b != [0-9] ] && [ $c != [0-9] ]; do
read b?"Not a number. Please enter a number: "
read c?"Not a number. Please enter another number: "
done

a=`expr b \\* c`
echo $a

...but the while loop is not evaluating, I am getting an error such as (assuming l and p were entered into the prompt)

Code:

myscript[50]: l: bad number

And when the entries are actual numbers, it still generates an error such as;
myscript[50]: [0-9]: syntax error

...so it does seem there is a syntax error with the while loop. Any idea?

Hi, what shell is this the syntax of?

Code:

read b?"Please enter a number: "

What happens when you enter the above as a command from the command prompt? Does it work? Normally, I would expect to see something like:

Code:

read -p "Please enter a number: " b

a=`expr b * c` will not work, needs to be a=`expr b \* c` to protect the * from being interpreted by the shell.

Also [ $c != [0-9] ] is not valid syntax, in bash/ksh93 you would need double square brackets [[ ... ]] and then this would test for a single digit..

Korn shell. I have updated the initial post to reflect this.

---------- Post updated at 02:11 PM ---------- Previous update was at 02:04 PM ----------

Yes, you are right, that was a forum typo on my part, it actually needed double backslahes for it to work.

Entering

Code:

read b?"Please enter a number: "

works just fine elsewhere, I just cannot get past this while loop.

---------- Post updated at 02:22 PM ---------- Previous update was at 02:11 PM ----------

Hello Gurus,

[[.....]] for each evaluation was a key point. I have to ensure each evaluation was put into double square brackets such as he following

while [[ $b != [0-9] ]] && [[ $c != [0-9] ]]; do

Thanx a million.
I'm not sure why the forum is bundling together all my responses even though I am responding to each response individually.