The Linux version of PaperCut NG is supplied in a self-extracting, self-installing archive. The archive is simply a tar archive compressed with gzip, and headed with a shell script to facilitate self-extracting. After extraction is complete, the installation script named install is executed to begin the install process. Some system administrators may like to inspect the contents of the archive, and possibly the installation process itself prior to the actual install. The self-extracting installer takes a number of command line arguments. The -e argument will extract the archive into the current working directory ready for inspection. Further options and documentation is available via the --help option.

  Usage: pcng-setup.sh [-e|-i|-l] [-v] [-n] [list ...]
     -e      Extract the files and then exit without installing.
     -i      Install after extracting the files (default).
     -l      List the contents of the archive and exit without extracting.
     -v      Verbose. Print the names of the files as they are extracted.
     list    The list of files to extract."
                

Even though the majority of the installation process is completed under the identity of the non-privileged user account called papercut, most administrators would like to know what the install process does. The main steps are outlined below:

    ~/server/bin/linux-i686/setperms
    ~/providers/print/linux-i686/setperms
                    

    ~/server/bin/linux-i686/roottasks
    ~/providers/print/linux-i686/roottasks
                    

CUPS, also known as the Common Unix Print System, is a popular system for managing printers on Linux servers. CUPS uses a chain-of-commands concept where filters and backends combine together to form a process steam - a workflow. PaperCut NG hooks into this workflow at the backend level intercepting the job before it's passed onto physical printer hardware.

The interception is done by wrapping or proxying the real CUPS backend. CUPS calls the PaperCut NG backend which processes the job. If the job is approved, it passes the document onto the real backend. If the job is denied, it is deleted and processes no further. The PaperCut NG backend is usually set up and installed by default during the standard installation.

Setting up the PaperCut NG CUPS backend proxy is a relatively simple task. All the administrator needs to do is prefix the existing DeviceURI with the papercut:. For example the entry:

    DeviceURI socket://192.168.1.200:9100
                

would become:

    DeviceURI papercut:socket://192.168.1.200:9100
                

The printer will register itself with the PaperCut NG system on the first print event.

Samba is used to provide file and print sharing to Windows systems and is a popular solution. One of the main reasons for its popularity is that it avoids the need for expensive Microsoft Windows server licenses!

Samba exposes the locally set up Linux/Unix printers as network shared Windows printers. It does this by wrapping the underlying print system - usually CUPS or LPR/LPD. In the case of LPR, Samba calls the standard lp command line programs to perform printing. PaperCut NG works by wrapping or proxying the "print command". More information on how Samba interacts with the underlying print system is available in the Samba documentation.

A typical entry in the Samba configuration file smb.conf defining the PaperCut NG print command wrapper would be:

 print command=/home/papercut/providers/print/linux-i686/samba-print-provider
    -u "%u" -J "%J" -h "%h" -m "%m" -p "%p" -s "%s" 
    -a "[standard print command]" &

 (IMPORTANT: The above information should appear all on the one line. 
 Note the use of the & (ampersand) on the end of the line.)
                

where [standard print command] is the command that would normally be called for printing.

The %u, %p, etc., are Samba substitution variables. These are replaced with content such as the username, printer name, etc. and are used by PaperCut NG in the reporting and logging.

The printer will register itself with the PaperCut NG web interface after the first print is received.