The hash symbol – also known as the pound/number sign, or even the octothorp(e) as Macworld reader Keith points out – was one of the more rarely used special characters until Twitter and Instagram ...

In Bash, a hash is a data structure that can contain many sub-variables, of the same or different kinds, but indexes them with user-defined text strings, or keys, instead of fixed numeric identifiers.

The first time I heard about hash tables was after taking a compilers course during my BSc. The truth is, I was not able to understand and appreciate their usefulness fully back then. Now that I know ...