While most technical hiring questions aren’t all that relevant, this one might be more generally useful. Find duplicate files; the trick was the speedup..
Learning a new computer language can be fun! Stretching ourselves to think about problems in new ways..
Building interactive commands that uses editing history and tab completion can be easy in bash and serve as a wrapper for automating tasks.
A colleague of mine once posted a hiring question to ask prospective developers: “What is the least significant 10 digits of the series: .. ?”
Many people use awk for one-liners; picking out fields from logs, doing pattern matching. It’s capable of so much more however. IMO, the “littleness” of the language is one of it’s strengths.
This article has a link to a simple script I’ve used for over a decade to detect corrupted files. It will detect and report on files that have changed, been added, deleted or possibly moved within the same directory structure.