Perl prints only one line when directed to a file but print to a screen works

vlad3848 has asked for the wisdom of the Perl Monks concerning the following question:

I am trying to print a list of the devices that match my specific criteria. When I print everything to the screen, it works great. However, when I print it to a file it only prints one line. I am new to perl so any help would be appreciated. Thanks

open OVERWRITE, ">overwrite.txt" or die $!  
$dbConnection = &openConnection();
# run the "list_device" command via the initial connection
my $device_list = $dbConnection->list_device();
foreach my $listDevices ($device_list->result()) {
    if (   ($listDevices->model !~ /PIX/)
        && ($listDevices->model !~ /ASA/)
        && ($listDevices->model !~ /ACE/)
        && ($listDevices->driverName !~ /Context/)
        && ($listDevices->hostName =~ /^ls1.*/i)
        && ($listDevices->vendor =~ /Cisco/)
    ) {
        #create device hash for LS
        $deviceHash{"deviceID"}         = $listDevices->deviceID;
        $deviceHash{"deviceType"}       = $listDevices->deviceType;
        $deviceHash{"vendor"}           = $listDevices->vendor;
        $deviceHash{"model"}            = $listDevices->model;
        $deviceHash{"primaryIPAddress"} = $listDevices > primaryIPAddr
+ess;
        $deviceHash{"hostName"}         = $listDevices->hostName;

        # mapping array
        my @returnData = (
            "deviceID",         "hostName",
            "primaryIPAddress", "deviceType",
            "vendor",           "model"
        );
                  
        # loop through the hash and print out the device information
        foreach my $data (@returnData) {
            my $returnDataLength = @returnData;

            if (exists $deviceHash{$data}) {
                                print OVERWRITE $deviceHash{$data} . "
+,";
                                }
        }
            }
    &closeConnection($dbConnection);
}
close OVERWRITE;
[download]

Comment on Perl prints only one line when directed to a file but print to a screen works Download Code

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Re: Perl prints only one line when directed to a file but print to a screen works by Happy-the-monk (Canon) on Jun 30, 2013 at 17:17 UTC
`foreach my $listDevices ($device_list->result()) { ... open OVERWRITE, ">overwrite.txt" or die $! ... close OVERWRITE; ... }` [download] Do you see what is happening? You have even called the filehandle "`OVERWRITE`". The file gets overwritten every time the loop and if directive come by the call to `open` Solution: place both the `open` and `close` outside of the foreach loop. `open` goes first, then the loop, and when that's done, `close` the filehandle. Cheers, Sören (hooked on the Perl Programming language)	[reply] [d/l]
Re^2: Perl prints only one line when directed to a file but print to a screen works by vlad3848 (Acolyte) on Jun 30, 2013 at 17:52 UTC
Thank you Sören!	[reply]
Re: Perl prints only one line when directed to a file but print to a screen works by hdb (Monsignor) on Jun 30, 2013 at 17:17 UTC
As you overwrite your file for every iteration of your outer loop, you might want to either open it outside the loop or open it for appending (in contrast to the name...).	[reply] [d/l]
Re^2: Perl prints only one line when directed to a file but print to a screen works by vlad3848 (Acolyte) on Jun 30, 2013 at 17:51 UTC
That solved it! Thank you very much!	[reply]