I found a code example in the webs, that solves a current problem of mine by using the the os process module.
(use-modules (os process))
(http://gnu-guile.7481.n7.nabble.com/getting-pipes-going-td14625.html#a14627)
That's cool, except I don't have that module, and don't know where and how to get it.
Can you help?
(I use Guile 2.0, on Debian.)
The module/library you are looking for is called "Guile Library" (guile-lib) and is introduced here (nongnu.org)
The function run-with-pipe
is documented here and the library may be downloaded here.