If, Elif, Else

#!/bin/bash

read -p "Enter your Age: " AGE

if [ $AGE -ge 80 ]

then

 echo "You are very old"

elif [ $AGE -ge 40 ]

then

 echo "You are old"

elif [ $marks -le 18 ]

then

 echo "You are very young"

elif [ $marks -le 30 ]

then

 echo "You are young"

else

 echo "You are the Rest"

fi