Perl5 リファレンス

       system LIST

       system PROGRAM LIST
               Does exactly the same thing as `exec LIST', except
               that a fork is done first, and the parent process
               waits for the child process to complete.  Note
               that argument processing varies depending on the
               number of arguments.  If there is more than one
               argument in LIST, or if LIST is an array with more
               than one value, starts the program given by the
               first element of the list with arguments given by
               the rest of the list.  If there is only one scalar
               argument, the argument is checked for shell
               metacharacters, and if there are any, the entire
               argument is passed to the system's command shell
               for parsing (this is `/bin/sh -c' on Unix
               platforms, but varies on other platforms).  If
               there are no shell metacharacters in the argument,
               it is split into words and passed directly to
               `execvp', which is more efficient.

               Beginning with v5.6.0, Perl will attempt to flush
               all files opened for output before any operation
               that may do a fork, but this may not be supported
               on some platforms (see the perlport manpage).  To
               be safe, you may need to set `$|' ($AUTOFLUSH in
               English) or call the `autoflush()' method of
               `IO::Handle' on any open handles.

               The return value is the exit status of the program
               as returned by the `wait' call.  To get the actual
               exit value divide by 256.  See also the exec entry
               elsewhere in this document.  This is not what you
               want to use to capture the output from a command,
               for that you should use merely backticks or
               `qx//', as described in the section on "`STRING`"
               in the perlop manpage.  Return value of -1
               indicates a failure to start the program (inspect
               $! for the reason).

               Like `exec', `system' allows you to lie to a
               program about its name if you use the `system
               PROGRAM LIST' syntax.  Again, see the exec entry
               elsewhere in this document.

               Because `system' and backticks block `SIGINT' and
               `SIGQUIT', killing the program they're running
               doesn't actually interrupt your program.

                   @args = ("command", "arg1", "arg2");
                   system(@args) == 0
                        or die "system @args failed: $?"

               You can check all the failure possibilities by
               inspecting `$?' like this:

                   $exit_value  = $? >> 8;
                   $signal_num  = $? & 127;
                   $dumped_core = $? & 128;

               When the arguments get executed via the system
               shell, results and return codes will be subject to
               its quirks and capabilities.  See the section on
               "`STRING`" in the perlop manpage and the exec
               entry elsewhere in this document for details.