Process Windows commands and get return code 4

[stevio]

Hi all,
Trying to run Windows command and process return code, then use return codes to process code

In Win Command line:

c:\command
results here
c:\echo %errorlevel%
30 (for example)

In Perl, I try to run the following code

$output = `command`;
$errorlevel = `echo %errorlevel%`;
print $output; #just to view results
print $errorlevel; #just to review results

$errorlevel always returns 0 instead of 30, because I think it is started in a different shell to the `command` system call.

How do I tie the two commands together so that I get the same result as running it from the command line?

Thanks
Steve

 

[mikevh]

my @output;
my $errorlevel=system(qq(command > myoutput));
if ($errorlevel) {
    print qq("command" returned status "$errorlevel");
} else {
    open(MYOUTPUT, "myoutput") || 
        die qq(Can't open "myoutput" for read\n);
    @output = <MYOUTPUT>;
    print qq($_\n) for (@output);
}

 

[stevio]

mikevh,

sorry, this didn't produce the correct result

result of running the script was

c:\command returned status 5888

Should be 30

Any other ideas??

 

[raklet]

Yes, use the special variable $?.

my $returned_text = `xcopy blah do`;
print $? >> 8;

The $? variable returns the error status generated by calls to the system function or by calls to functions enclosed in back quotes, as in the following:

$username = 'hostname';


The error status stored in $? consists of two parts:

* The exit value (return code) of the process called by system or specified in back quotes
* A status field that indicates how the process was terminated, if it terminated abnormally

The value stored in $? is a 16-bit integer. The upper eight bits are the exit value, and the lower eight bits are the status field. To retrieve the exit value, use the >> operator to shift the eight bits to the right:

$retcode = $? >> 8;

Alternatively, you can divide the error return variable by 256 and get the same result.

my $returned_text = `xcopy blah do`;
print $? / 256;

 

[stevio]

Thanks heaps Raklet, that did the job!

 

[envetri]

hi cheungs
i would be of great help to understand it better if you can post the simple working script

 

[mikevh]

Yes, thanks, raklet. I'll remember that, I hope.

 

[stevio]

envetri,

I basically replicated what Raklet suggested

$output = `windows command here`; # produces a return code
$retval =$?/256; # $? is the return code from Win command
print "Return code is: ",$retval,"\n";
if ($retval eq 23)
{
do this;
}
elsif ($retval eq 24)
{
do that;
}
else
{
etc etc;
}

Works beautifully. I just had no idea how to get the return value into a variable using Perl...until now.

HTH
Steve

 

[PaulTEG]

Nice one rak
--Paul

 

[raklet]

Thank you.