Arithmetic shell script:

To carry out arithmetic operation on variable have to use the command expression catch is able to carry arithmetic operation.

Ex: 

a=10 

b=5

echo  expression $ a+$b

echo expression $ a/*$b

  while evaluating an expression expression perform various arithmetic according to the following priorities.

Four decision making 

a) if -then-fi

b)if-then-fi

c)if-max-if-else-fi

d)case-asac

if-then-else if statement 

if(control command)

then statement

else statement

if 

read number

if($number - &to)

then 

echo regestive integer

else

echo positive number

is