S9 LIB  (spawn-command string)  ==>  list
        (spawn-command/fd string)  ==>  list

        (load-from-library "spawn-command.scm")

Spawn an inferior process running the command STRING. Return a
list of two I/O-ports and the PID of the inferior process:

        (input-port output-port integer)

The input-port can be used to read the output of the command and
the output-port to send input to the command. The command will be
executed by running the equivalent of:

        execl("/bin/sh", "/bin/sh", "-c", STRING, NULL);

Error output of the child will be redirected to its standard output.

SPAWN-COMMAND/FD is like SPAWN-COMMAND, but delivers raw Unix file
descriptors instead of input/output ports.

(spawn-command "ls -l /bin")
  ==>  (#<input-port> #<output-port> 707)
