UNIX for Dummies Questions & Answers

Hi All,
I am new to shell script.
I wrote a very small script that takes only digits as input-
but there is some problem in that.can you help me in debugging that.

#!/bin/ksh
echo "Digits as input"
read number
digit='eval [0-9][0-9][0-9]'
if [[ number -eq $digit ]]
then
echo "Entered number is a digit"
else
echo "0"
fi

Please modify this one or without AWK give me some inputs.

Thanks,
Namish

Code:

#!/bin/ksh
echo "Digits as input"
read number

test=`echo "$number" | egrep "^[0-9]+$"`

if [ "$test" ]
then
   echo "Entered number is a digit"
else
   echo "0"
fi

Thanks robotronic.

I appericiate your help and quick reply.

Thanks
Namish