Function: system
Section: programming/specific
C-Name: gpsystem
Prototype: vs
Help: system(str): str being a string, execute the system command str.
Doc: \var{str} is a string representing a system command. This command is
 executed, its output written to the standard output (this won't get into your
 logfile), and control returns to the PARI system. This simply calls the C
 \kbd{system} command.
