#!/bin/bash
# case $variable in 
read -p "Enter an animals name: " animal
echo -n "A $animal has "
case $animal in
horse|cow|cat) echo -n "four ";;
man|woman) echo -n "two ";;
*) echo -n "an unknown number of ";;
esac
echo "legs!"


Select 

select fname in *;
 do              
 echo you picked $fname \($REPLY\) 
  break;        
 done

Type echo * to see how it works 



((...))
         (( expression ))

[[...]]
         [[ expression ]]

Return a status of 0 or 1 depending on the evaluation of the conditional expression expression. 

( expression )
Returns the value of expression. This may be used to override the normal precedence of operators.

! expression
True if expression is false.

expression1 && expression2
True if both expression1 and expression2 are true.
mkdir d && cd d ; pwd 

expression1 || expression2
True if either expression1 or expression2 is true.


The   && and || operators do not evaluate expression2 if the value  of  expression1 is sufficient to determine the return value of the  entire  conditional expression.