Base conversion in BASH

As programmers, we often encounter numbers written in binary or hexadecimal format. Mostly it is written as the context is made easier. For example, a set of flags is better represented as binary than integer. Here's an example :-

#define IS_TRUE        0b01     // same as 1
#define IS_FALSE       0b00     // same as 0
#define CONFIRM        0b10     // same as 2
#define DOUBTFUL       0b00     // same as 0

This example might not be very common, but this demonstrates the use of binary representation. These flags are useful at binary level to facilitate " bit-level AND " and various other operations.

In such scenarios, it could get confusing as to what the number represents in integers. Many, here, would suggest creating a program in the language of your choice and using it for base conversion. So, here I explain how one can use BASH itself.

BASH allows base conversion very easily. Fire up a terminal and try this :-

echo $((2#1010101))

I assume, I needn't explain $((<operation>)) is necessary for mathematical operations in BASH.  The output of the above command is 85, which is the decimal value of the number  "0b1010101".

So here we have a simple base converter. Interestingly, the base conversion allows to convert from any base to decimal this easily  :

<base>#<number_in_base>
The above is sufficient to convert number given in any base to decimal value. Go ahead, try it out.