In Go
https://go.dev/ https://gobyexample.com/
# Install Go with brew (OSX) or see https://go.dev/doc/install
brew install go
go version # --> 1.17.*
go run main.go ./input # input dir assumed to contain `day1/input.txt`, etc.
go test ./...
Note to future self: I forgive you for giving up on this because the challenges got too long.