Here's one I don't think was overengineered
I wrote this back in June 2004
As part of the Perl Quiz of the Week
Within weeks, it had become something I used every day
It's a Perl replacement for grep
Once again, it was motivated by a frequently-typed pipeline:
find . -type f | xargs grep pattern
But also by some other irritations:
ftail main/current | grep badmailfrom | dnsfilter
Because of stdio buffering, this is hardly ever up to date
My system's grep had no option to disable buffering
Another irritation: grep patterns are inferior to Perl patterns
grep 'foo|bar' somefile # Wrongo
grep '(abc).*1円' somefile # Wrongo