To calculate two variables in bash, we can use the `\$((...))` operator to perform arithmetic operations.

For example, suppose we have two variables, `a` and `b`, and we want to calculate the sum of `a` and `b`. We can use the following syntax:

``````ab=\$((a + b))
``````

This calculates the sum of `a` and `b` and stores the result in the `ab` variable.

\$((...)) operator can be used to perform other arithmetic operations, such as:

• subtraction

• multiplication

• division.

• For example:

``````result=\$((a - b))  # Subtract b from a
result=\$((a * b))  # Multiply a and b
result=\$((a / b))  # Divide a by b
``````
Note:

Note that the \$((...)) operator only supports integer arithmetic, so if we need to perform floating-point arithmetic - we need to use a tool like bc.

## Divide two variables in bash

``````a=4;
b=2;
echo \$((a / b))
``````

The result from this operation is:

``````2
``````

## awk to calculate two variables

As an alternative solution we can use the command: `awk`. The following example shows the usage of `awk` command to multiple or sum two bash variables:

``````awk -v a=5 -v b=2 'BEGIN { print  ( a * b ) }'
awk -v a=5 -v b=2 'BEGIN { print  ( a + b ) }'
``````

The result of these commands is:
10
7