#! /bin/bash

N_CPUS=$(nproc 2> /dev/null || gnproc 2> /dev/null || sysctl -n hw.ncpu 2> /dev/null)

main() {
    local -r dir="${1-$HOME}"
    local -r jobs="${1-$N_CPUS}"

    # XXX Just doing 'rm -rf' because 'cargo clean' starts doing extra work
    #     and in some cases even downloads new deps, etc.
    find "$dir" -type f -name Cargo.toml -print0 \
    | xargs -0 -I % -P "$jobs" sh -c 'rm -rf $(dirname "%")/target'
}

main "$@"