Arithmetic Operators in Unix: In Unix we have capability to add, subtract, multiply, division of arithmetic values.

- + (Addition) – To add values on any side of the operator.

**Ex:**

`expr $a + $b`

- -(Subtraction) – To subtract right hand operand from left hand operand.

**Ex:**

`expr $a - $b`

- *(Multiplication) – To multiply the values on either side of the operator.

**Ex:**

`expr $a \* $b`

**Note:**

* is the special character in Unix and whenever we use special character, we should prefix with the symbol \ .

- / (Division) – To divide the left-hand operand by right hand operand.

**Ex:**

`expr $b / $a`

- % (Modulus) – To divide the left-hand operand by right hand operand and returns remainder

**Ex:**

`expr $b % $a`

- = (Assignment) – To assign the right operand in left operand. The value of b will be assigned to variable a.

**Ex:**

a = $b

- == (Equality) – To compare the 2 numbers. If both are same then it will return True else it will return False.

**Ex:**

[ $a == $b ]

- != (Not Equality) – To compare the two numbers. If both are different then it will return true.

**Ex:**

[ $a != $b ]

In Unix, it is very important to know that all the conditional expressions should be inside the square braces with the space.

**For Ex:**

[ $a == $b ] is correct.

[$a==$b] is incorrect.

**Ex:**