Shell Programming and Scripting

#!/bin/bash
echo "Guess my secret number (0-100): "
number=$((RANDOM%100+0))
echo "$number"
read GUESS

if echo $GUESS | grep "^[0-9]*$">aux
then
  echo "good"
else
  echo "bad"
fi
rm aux

if [ -n "$( print - "$GUESS"           |\
            sed 's/^[+-]//;s/[0-9]//g;s/\.//'   \
          )" ] ; then
     echo "good"
else
     echo "bad"
fi

[/tmp]$ cat try.sh
#! /bin/sh

echo "Guess my secret number (0-100): "
read GUESS

if [[ $GUESS -ge 0 && $GUESS -le 100 ]] ; then 
  echo "good"
else
  echo "bad"
fi