NAME

lpfilter − administer filters used with the LP print service

SYNOPSIS

/usr/lib/lpfilter −f filter-name −F path-name
/usr/lib/lpfilter −f filter-name −
/usr/lib/lpfilter −f filter-name −i
/usr/lib/lpfilter −f filter-name −x
/usr/lib/lpfilter −f filter-name −l

DESCRIPTION

The lpfilter command is used to add, change, delete, and list filters used with the LP print service.  These filters are used to convert the content type of a file to a content type acceptable to a given printer.  One of the following options must be used with the lpfilter command: −F path-name (or − for standard input) to add or change a filter, −i to reset an original LP print service filter to its factory setting, −x to delete a filter, or −l to list a filter description. 

The argument all can be used instead of a filter-name with any of these options.  When all is specified with the −F or − option, the requested change is made to all filters.  Using all with the −i option has the effect of restoring to their original settings all filters for which predefined settings were initially available.  Using the all argument with the −l option produces a list of all filters, and using it with the −x option results in all filters being deleted. 

Adding or Changing a Filter

The filter named in the −f option and described in the input is added to the filter table.  If the filter already exists, its description is changed to reflect the new information in the input.  Once added, a filter is available for use. 

The filter description is taken from the path-name if the −F option is given or from the standard input if the − option is given.  One of the two must be given to define or change a filter.  If the filter named is one originally delivered with the LP print service, the −i option will restore the original filter description. 

Filters are used to convert the content of a request into a data stream acceptable to a printer.  For a given print request, the LP print service will know the following:

− the type of content in the request

− the name of the printer

− the type of the printer

− the types of content acceptable to the printer

− the modes of printing asked for by the originator of the request

It will use this information to find a filter that will convert the content into a type acceptable to the printer. 

Below is a list of items that provide input to this command and descriptions of each item.  All lists are separated by commas or spaces. 

Input types: content-type-list
Output types: content-type-list
Printer types: printer-type-list
Printers: printer-list
Filter type: filter-type
Command: shell-command
Options: template-list

Input types
This gives the types of content that can be accepted by the filter.

Output types
This gives the types of content that the filter can produce from any of the input content types.

Printer types
This gives the type of printers for which the filter can be used. The LP print service will restrict the use of the filter to these types of printers.

Printers
This gives the names of the printers for which the filter can be used. The LP print service will restrict the use of the filter to just the printers named.

Filter type
This marks the filter as a “slow” filter or a “fast” filter. Slow filters are generally those that take a long time to convert their input. They are run unconnected to a printer to keep the printers from being tied up while the filter is running. Fast filters are generally those that convert their input quickly or those that must be connected to the printer when run. These will be given to the interface program to run connected to the physical printer.

Command
This specifies the program to run to invoke the filter. The program name as well as fixed options are included in the shell-command; additional options are constructed, based on the characteristics of each print request and on the Options field.  The command must accept a data stream as standard input and produce the converted data stream on its standard output. This allows filter pipelines to be constructed to convert data not handled by a single filter.

Options
This is a list of templates separated by commas used by the LP print service to construct options to the filter from the characteristics of each print request listed in the table later. In general, each template is of the following form:

keyword pattern = replacement

The keyword names the characteristic that the template attempts to map into a filter-specific option; each valid keyword is listed in the table below.  A pattern is either a literal pattern of one of the forms listed in the table or a single asterisk, ∗; if the pattern matches the value of the characteristic, the template fits and is used to generate a filter-specific option.  A pattern of ∗ matches any value.  The replacement is a string used as a filter-specific option with an embedded asterisk, ∗, replaced with the value of the characteristic. 

For example, the template

MODES landscape = −l

would show that if a print request includes the −y landscape option, the filter should be given the option −l.  As another example, the template

TERM * = −T *

would show that the filter should be given the option −T printer-type for whichever printer-type is associated with a print request using the filter. 

When an existing filter is changed with this command, items that are not specified in the new information are left as they were.  When a new filter is added with this command, unspecified items are given default values. 

Note that a filter name and a command must be given.  A filter with no input type value is assumed to work with any input type; this is also true for the output type, printer type, and printer values. 

Deleting a Filter

The −x option is used to delete the filter specified in filter-name from the LP filter table. 

Listing a Filter Description

The −l option is used to list the description of the filter named in filter-name.  If the command is successful, the following message is sent to standard output:

Input types: content-type-list
Output types: content-type-list
Printer types: printer-type-list
Printers: printer-list
Filter type: filter-type
Command: shell-command
Options: template-list

If the command fails, an error message is sent to standard error. 

SEE ALSO

lpadmin(1M), lp(1). 

\*U  —  Version 1.0