Running Linux, 5th Edition - Matthias Kalle Dalheimer [290]
That said, you may need to know about these files and directories. The CUPS configuration files reside in /etc/cups. The cupsd.conf file, as already noted, controls the server on a broad level, and you may need to edit this file. Other important files in this directory include printers.conf (which defines local printers) and lpoptions (which identifies the default printer). The ppd subdirectory holds PPD files for local printers (they're copied from elsewhere, as described shortly).
CUPS stores a great deal of support data in the /usr/share/cups directory tree. Of particular interest is the /usr/share/cups/model subdirectory, which holds PPD files (most in subdirectories named after the printers' manufacturers). The Foomatic and GIMP Print packages may install PPD files there. If they don't, and if you can't get these printer definitions recognized, try creating symbolic links in this subdirectory to the actual location of the printer definition package's PPD files. This should enable CUPS to locate the PPD files and install the printers.
In actual operation, CUPS uses the /var/spool/cups subdirectory to hold print job descriptions and the actual print job files. This directory is owned by root and the lp group and has 0710 (rwx--x---) permissions. CUPS also uses the /var/spool/cups/tmp directory, which is owned by root and the lp group and has 1710 (rwx--x--T) permissions. (These owners and permissions are typical, but may differ between distributions.) Unlike LPD, CUPS doesn't use separate subdirectories for each printer; print jobs for all printers are dumped into the same directory tree.
Chapter 15. File Sharing
In this chapter we give you a quick guide to the two major ways in the Linux world to share resources between systems. First we cover Samba, which uses Microsoft Windows networking protocols to allow users on one system to read and write files on another system, and to send jobs to printers on remote systems. The advantage of using Samba is that Linux and Unix can be integrated almost seamlessly with Microsoft systems, both clients and servers. The Microsoft Windows networking protocols can be used for sharing of files between Linux systems, although the preferred protocol for that really is the NFS protocol.
We present both NFS and NIS, protocols developed by Sun Microsystems and used by Unix systems for decades. NFS, the Network File System, allows systems to share files between Linux and Unix systems in a manner similar to Samba. NIS, the Network Information System, allows user information to be stored in one place and accessed by multiple systems so you don't have to update all the systems when a user or password changes. Although NIS is not a tool for file and printer sharing, we present it in this chapter because it shares some components with its cousin NFS, and because it can make NFS easier to administer because NIS allows each user to have the same account number on all systems.
NFS and NIS are useful at sites where only Linux and variants of Unix are connected. Versions have been created for Microsoft systems, but they are not particularly robust and have never become popular.
Microsoft provides a complimentary NFS client and server implementation for Windows systems that has not been adopted into common use despite it being free of cost. The Microsoft Windows Services for Unix (SFU ) package includes an NIS server and over 300 Unix utilities for use under Windows. Even given this free availability Windows sites that wish to secure interoperability between Windows network clients and Linux systems prefer the use of Samba.
In addition to MS Windows networking protocols and NFS, there are several well known file and print sharing protocols. Linux has support for NetWare-style file and print sharing using IPX protocols , Macintosh-based file and print sharing (AppleTalk protocol), file sharing over protocols such as FISH (File Sharing over SSH), as well as WebDAV-based file services. We do not cover these protocols in this chapter.
Sharing