Thanks John and David. :)
On Mar 11, 2004, at 4:38 PM, John W. Krahn wrote:
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
-- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
-- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
