WYNTK: UNIX System Admininistrator

Files need to be translated into a format that printers recognize.

Files on a computer may be stored in any number of formats. For example, a word processor might save a file in its own special format (such as RTF), or a graphics program might keep files in a format like TIFF or GIF. Sometimes you may even edit a file in a markup language (for example, troff or TeX). Many files (for example, mail files) are kept in a no-frills text format, sometimes known as ASCII format.

X users may be able to preview PostScript files

If you have a graphical terminal (like an X terminal), you may be able to “preview” files before you actually print them to a printer. By previewing a file, you can see on your screen exactly what will appear on the printer.

The advantage of previewing files is that you can save paper and also save a trip across the hall to the printer room. For many people, previewing comes in most useful when fine-tuning a document. If all you’re doing is tweaking a figure until it’s placed perfectly on a page, then you may need to repeatedly change the source file, print, and walk to the printer to see what it looks like, over and over again until you get it right. Being able to preview files doesn’t take the place of a true WYSIWYG editor, but it does save that portion of the carpet between your desk and the printer.

Printers don’t understand all of these formats. Printers have their own internal languages to tell them where to place characters, how to draw pictures, when to eject ...