Yeah I do the same sometimes, at the risk of going too deep into personal preference. A couple of notes about that approach:

1. I don't recommend using shell functions or aliases for this (e.g., `bashrc`) because then these scripts can't be called from other contexts, e.g., like Vim and Emacs builtin support for shell commands. This can easily be solved by creating scripts that can be called from anywhere (my personal collection of these scripts is here https://github.com/robenkleene/Dotfiles/tree/master/scripts). Personally, I only use Bash functions for things that have to do with Bash's runtime state (e.g., augmenting PATH is a common one).

2. The more important part though, is I don't always want to search in `*.foo`, I want a flexible, well-designed, API that allows me to on-the-fly decide what to search.

#2 is particularly important and drifts in philosophy of tooling, a mistake I used to make is building my workflow today into customizations like scripts. This is a bad idea because then the scripts aren't useful as your tasks change, and hopefully your tasks are growing in complexity over time. I.e., don't choose your tools based on your workflow today, otherwise you're building in limitations. Use powerful tools that will support you no matter what task you're performing, that scale practically infinitely. "The measure of a bookshelf is not what has been read, but what remains to be read."