Help programming printer

[jse]

I'm not sure if this is the correct place to ask this question, my 
appologies if it is not. 
 
I am trying to port an old MS-DOS program and I have run into a stumbling  
block.  The Mess Dos program wrote directly to the printer.  I can't seem  
to find much information on how to print from a program in Linux.  Can 
anyone recommend information on a web page, a book, or the correct mailing 
list to ask this question?  Or am I just making this too hard?  
   
Thanks  
  -Scott