For basic load/munge/save stuff (like CSV processing) the C standard library more than suffices, and is cross-platform. You don't need OS-dependent stuff (like POSIX) to do that.
(I'm not arguing C vs. Rust though... just pointing out that "cross-platform" is a much more meaningful descriptor for a CLI tool than "in Rust". The latter just reads like noise to me.)
(I'm not arguing C vs. Rust though... just pointing out that "cross-platform" is a much more meaningful descriptor for a CLI tool than "in Rust". The latter just reads like noise to me.)