Linux Terminal: How to do fuzzy search with tre-agrep

Grep is the best tool to search in big file for a specific pattern, or a specific process in the complete list of running processes, but it has a small limit, it searches for the exact string that you ask, and sometime it could be useful to do an ???approximate??? or ???fuzzy??? search.

For this goal the program agrep was firstly developed, but it’s closed source, but luckily there is an open source source alternative: tre-agrep