🚀 go-pugleaf

>Is it possible (in sh or in csh) to execute a program that is read from
>stdin?

It's possible, although the ways you can do it depend on whether the
"program" is an executable image or a script.

If it's a script, you can try piping it to the interpreter (shell or
whatever).

If it's an executable image, in most UNIXes you must either put it into a
file, or construct some program that reads its standard input and sets
up its address space to contain the executable image it's reading and
then jumps to it.