Silky Manwani wrote:
>
> Hello,
Hello,
> Back with the system command but with a different problem.
>
> I am calling a program with the system command which has arguments.
> This program returns a string and I need to capture it.
>
> @args("command","arg1","arg2");
> $res = system(@args);
>
> print $res;
>
> It prints 0;
>
> But before that it prints the string that the program or command
> returned..!!!
> How do I capture the return value or $res as I need to work with $res
> further.!!
>
> $exit_value = $? >> 8;
> This didn't help..
Did you read the documentation for the system function?
perldoc -f system
system LIST
system PROGRAM LIST
Does exactly the same thing as `exec LIST', except
that a fork is done first, and the parent process
waits for the child process to complete. Note
that argument processing varies depending on the
number of arguments. If there is more than one
argument in LIST, or if LIST is an array with more
than one value, starts the program given by the
first element of the list with arguments given by
the rest of the list. If there is only one scalar
argument, the argument is checked for shell
metacharacters, and if there are any, the entire
argument is passed to the system's command shell
for parsing (this is `/bin/sh -c' on Unix
platforms, but varies on other platforms). If
there are no shell metacharacters in the argument,
it is split into words and passed directly to
`execvp', which is more efficient.
Beginning with v5.6.0, Perl will attempt to flush
all files opened for output before any operation
that may do a fork, but this may not be supported
on some platforms (see the perlport manpage). To
be safe, you may need to set `$|' ($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.
Please read the third paragraph carefully and come back if you have any more questions.
John
--
use Perl;
program
fulfillment
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