Thank you!

cc pipes is a separate command that you call to move to pipes subcontext. Then you don't need do\in do\par or cc .. you just call functions directly like x> echo "Hello" |append-to-file "file.txt".

It would be an improvement if you could you make function that accept file accept rye-file instead of string? echo "Hello" |append-to-file %file.txt

you can test stdin if you create a rye script test.rye where for example do\par pipes { stdin |out } and then call it for example cat somefile.txt |rye test.rye