cfunction
src/core/io.c on line 122, column 1
(file/popen command &opt mode) (DEPRECATED for os/spawn)
Open a file that is backed by a process. The file must be opened in
either the :r (read) or the :w (write) mode. In :r mode, the stdout
of the process can be read from the file. In :w mode, the stdin of
the process can be written to. Returns the new file.