#!/bin/sh

val=`expr 2 + 2`

echo "Total value : $val"

a=20

b=10

add=`expr $a + $b`

sub=`expr $b - $a`

mul=`expr $a \* $b`

div=`expr $b / $a`

mod=`expr $b % $a`

equality=`expr [ $b == $a ]`

notequal=`expr [$b != $a]`

assigment=`expr a = $b`

echo "Addition : $add"

echo "Subtraction : $sub"

echo "Multiplication : $mul"

echo "Division : $div"

echo "Modulus : $mod"

echo "Equality : $equality"

echo "Not Equal : $notequal"

echo "Assignment : $assigment $a $b"

equal=[ $b -eq $a ]

notequal2=`expr [ $b -ne $a ]`

greaterthan=`expr [ $b -gt $a ]`

lessthan=`expr [ $b -lt $a ]`

greaterthanequal=`expr [ $b -ge $a ]`

lessthanequal=`expr [ $b -le $a ]`

echo "Equality(relational) : $equal"

echo "Not Equal : $notequal2"

echo "greater than : $greaterthan"

echo "less than : $lessthan"

echo "greater than equal : $greaterthanequal"

echo "less than equal : $lessthanequal"

#Boolean Operators

#logical negation

#[ ! false ] is true.

#logical OR

#[ $a -lt 20 -o $b -gt 100 ] is true.

#logical AND

#[ $a -lt 20 -a $b -gt 100 ] is false.

#String Operators

#[ $a = $b ] is not true.

#[ $a != $b ] is true.

#Checks if the given string operand size is zero; if it is zero length, then it returns true.

#[ -z $a ] is not true.

#Checks if the given string operand size is non-zero; if it is nonzero length, then it returns true.

#[ -n $a ] is not false.

#Checks if str is not the empty string; if it is empty, then it returns false.

#[ $a ] is not false.