filter
job user title num-copies options [
filename
]
DESCRIPTION
The CUPS filter interface provides a standard method for adding support for
new document types to CUPS. Each filter is capable of converting from one
or more input formats to another format that can either be printed directly
or piped into another filter to get it to a printable format.
Filters must be capable of reading from a filename on the command-line
or from the standard input, copying the standard input to a temporary
file as required by the file format. All output must be sent to the
standard output.
The command name (argv[0]) is set to the name of the destination printer.
LOG MESSAGES
Messages sent to stderr are generally logged to
printer-state-message attribute and the current ErrorLog.
Each line begins with a standard prefix:
ALERT: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "alert" log level.
ATTR: attribute=value [attribute=value]
Sets the named job attribute(s). Typically this will be used to
set the job-remote-id attribute.
CRIT: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "critical" log level.
DEBUG: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "debug" log level.
DEBUG2: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "debug2" log level.
EMERG: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "emergency" log level.
ERROR: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "error" log level.
INFO: message
Sets the printer-state-message attribute. If the current LogLevel
is set to "debug2", also adds the specified message to the
current ErrorLog using the "info" log level.
NOTICE: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "notice" log level.
PAGE: page-number #-copies
PAGE: total #-pages
Adds an entry to the current PageLog. The first form adds
#-copies to the job-media-sheets-completed attribute. The second
form sets the job-media-sheets-completed attribute to #-pages.
Sets, adds, or removes printer-state-reason keywords to the
current queue. Typically this is used to indicate media, ink, and
toner conditions on a printer.
WARNING: message
Sets the printer-state-message attribute and adds the specified
message to the current ErrorLog using the "warning" log level.
ENVIRONMENT VARIABLES
The following environment variables are defined by the CUPS
server when executing the filter:
CHARSET
The default text character set, typically utf-8.
CLASS
When a job is submitted to a printer class, contains the name of
the destination printer class. Otherwise this environment
variable will not be set.
CONTENT_TYPE
The MIME type associated with the file (e.g.
application/postscript).
CUPS_DATADIR
The directory where data files can be found.
CUPS_SERVERROOT
The root directory of the server.
DEVICE_URI
The device-uri associated with the printer.
FINAL_CONTENT_TYPE
The MIME type associated with the printer (e.g.
application/vnd.cups-postscript).
LANG
The default language locale (typically C or en).
PATH
The standard execution path for external programs that may be run by
the filter.
PPD
The full pathname of the PostScript Printer Description (PPD)
file for this printer.
PRINTER
The name of the printer.
RIP_CACHE
The recommended amount of memory to use for Raster Image
Processors (RIPs).
SOFTWARE
The name and version number of the server (typically CUPS/1.2).
TZ
The timezone of the server.
USER
The user executing the filter, typically "lp" or "root"; consult the
cupsd.conf(5) file for the current setting.
COMPATIBILITY
While the filter interface is compatible with System V interface
scripts, it will only work with the System V interface script as the
only filter. Typically the interface script will be provided via the
lpadmin(8) command using the -i option.
