system command
              Executes  command  via the system(3) call.  Differs
              from exec in that system doesn't  return  the  exe-
              cuted  command's  standard  output  as  the  result
              string, and system goes through the Unix  shell  to
              provide wildcard expansion, redirection, etc, as is
              normal from an sh command line.  The exit  code  of
              the command is returned.

              This command is provided by Extended Tcl.