"so are you reimplementing..." <- That is not it. I dont reimpelembt those programs, i implement needed features(when i cant just do the same with std lib, i did not need any grep features tho since rust Strings are so easy to work with). Here is some examples: https://github.com/XDream8/kiss-rs/blob/main/src/source.rs#L217 https://github.com/XDream8/kiss-rs/blob/main/src/source.rs#L248 https://github.com/XDream8/kiss-rs/blob/main/src/checksum.rs#L86 https://github.com/XDream8/kiss-rs/blob/main/src/lib.rs#L215 https://github.com/XDream8/kiss-rs/blob/main/src/build.rs#L209