6.2. LPD

LPD, the original BSD Unix Line Printer Daemon, has been the standard on Unix for years. It is available for every style of Unix, and offers a rather minimal feature set derived from the needs of timesharing-era computing. Despite this somewhat peculiar history, it is still useful today as a basic print spooler. To be really useful with modern printer, a good deal of extra work is needed in the form of companion filter scripts and front-end programs. But these exist, and it does all work.

LPD is also the name given to the network printing protocol by RFC 1179. This network protocol is spoken not only by the LPD daemon itself, but by essentially every networked print server, networked printer, and every other print spooler out there; LPD is the least common denominator of standards-based network printing.

LPRng(see Section 6.3) is a far better implementation of the basic LPD design than the regular one; if you must use LPD, consider using LPRng instead. There is far less voodoo involved in making it do what you want, and what voodoo there is is well documented. LPRng is essentially an enhanced LPD implementation with better security and extra features.

There are a large number of LPD sources floating around in the world. Arguably, some strain of BSD Unix is probably the official owner, but everyone implements changes willy-nilly, and they all cross-pollinate in unknown ways, such that it is difficult to say with certainty exactly which LPD you might have. Of the readily available LPDs, GNUlpr offers one with a few minor modifications that make the user interface much more flexible. The GNUlpr supports command-line option specification with a-o flag; options are then passed through to filters. This is similar to the features offered by a number of traditional Unix vendors, and similar to (although incompatible with) LPRng's -z option mechanism.

If you go with LPD, the best way to use it is via a front-end. There are several to chose from; KDEPrint, GPR (see Section 3.4) and XPP are perhaps the best. Others exist; tell me about them.