AAMOF, there is already a builtin feature that allow control of bash history.

It is called … HISTCONTROL.

HISTCONTROL

A colon-separated list of values controlling how commands are saved on the history list:

ignorespace lines which begin with a space character are not saved in the history list
ignoredups don’t save lines matching the previous history entry
ignoreboth short for ignorespace:ignoredups
erasedups remove all previous lines matching the current line from the history list before the current line is saved

Check this on the internet, you’ll see it fulfills your needs.

Thanks anyway for your Ruby code.

KUTGW !

– Philippe Petrinko