Add an IP printer with command line
You can use lpadmin

lpadmin -E -p "PrinterName" -v "PrinterURL" -P "PPD" -o printer-is-shared=false


-E Enables the printer
"PrinterName" can be anything that describes your printer
"PrinterURL" is the URL or IP address of the printer
-P "PPD" is the PPD file you wish to use  (including the path)
-o printer-is-shared=false turns off printer sharing


The PPD files are usually located in the /etc/cups/ppd directory.  If the printer you want to use is not listed, you can download the PPD from the OpenPrinting site.