Does exactly the same thing as
, except that a fork is
done first and the parent process waits for the child process to
exit. 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
/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
, which is
more efficient. On Windows, only the
system PROGRAM LIST
reliably avoid using the shell;
, even with more than one
element, will fall back to the shell if the first spawn fails.
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 perlport). To be safe, you may need
($AUTOFLUSH in English) or call the
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, shift right by eight (see
below). See also exec. 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 `STRING` in perlop. Return value of -1
indicates a failure to start the program or an error of the wait(2) system
call (inspect $! for the reason).
are ignored during the execution of
system, if you expect your program to terminate on receipt of these
signals you will need to arrange to do so yourself based on the return
If you'd like to manually inspect
system's failure, you can check all
possible failure modes by inspecting
Alternatively, you may inspect the value of
calls from the POSIX module.
Portability issues: system in perlport.