How can I print Shipment Confirmation form SO642000 automatically upon status changing to Confirmed?

What version are you running?  I believe this would be easy with the new workflow capabilities.

I’d do this with a customization. You’d want to create a field updated event handler for the status field, check if the status switched to confirmed, and if it has, print the document. It should look something like this:
 

public class SOShipmentEntryExt : PXGraphExtension<SOShipmentEntry>
    {

        protected void _(Events.FieldUpdated<SOShipment.status> e)
        {
            var row = (SOShipment)e.Row;
            if (row == null) return;

            if ((string)e.OldValue != "F" && (string)e.NewValue == "F")
            {
                Dictionary<string, string> printParams = new Dictionary<string, string>();
                printParams["Shipment Nbr"] = row.ShipmentNbr;

                PXReportRequiredException ex = null;
                ex = PXReportRequiredException.CombineReport(ex, "Report ID", printParams);

                PX.SM.SMPrintJobMaint.CreatePrintJobGroup("Device Hub Printer Name", ex, "Report Name");
            }


        }
    }

Of course you’ll want to fill this out with your information, for example put your actual Report ID instead of literally “Report ID”. It still needs to be in quotes though. Also, make sure your parameters actually match for the report you’re trying to print. I just threw this together real quick as an example.

Also note, “F” is the value the database stores for confirmed shipments. That’s why that’s there.

@jknauf 

Thanks for the insight on this one. I am to the same point that @gpineda64 was at that the PDF opening once confirmed. The script you wrote makes sense, but I want to be sure I am putting it in the correct place. 

Under what portion of the customization would you place this script?