system cmdstr1 ?cmdstr2...?
          Concatenates  cmdstr1,  cmdstr2 etc with space  separa-
          tors (see the concat command) into a single command and
          then evaluates the command using  the  standard  system
          shell.  On Unix systems, this is /bin/sh and om Windows
          its command.com.  The  exit  code  of  the  command  is
          returned.

          This command differs from the exec command in that sys-
          tem doesn't return the executed command's standard out-
          put 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.

          This command is provided by Extended Tcl.