As dicas parecem estar no primeiro link da sua pergunta. Pesquisas indicam que backends são apenas scripts. Então você pode simplesmente escrever o seu próprio. No entanto, parece que o script que você está procurando disponível para o OpenSuse é descrito em seu primeiro link.
% bl0ck_qu0te%encontrar esse script é complicado pelo fato de o OpenSuse agora usar instaladores de um clique e ter que cavar um pouco mais para encontrar o .rpm que contém o script. Aqui está um exemplo tirado diretamente de cups-backends-1.1-296.6.noarch.rpm disponível aqui.
Abrindo o pacote com o rolo de arquivo e navegando até /./usr/lib/cups/backend/ dentro do pacote, e abrindo pipe revela o script abaixo:
#! /bin/bash
# CUPS wrapper backend "pipe" for printing to any program.
# It forwards the print job data like a pipe into another command.
# Author: Johannes Meixner <[email protected]>, 2009, 2014
# For basic information see "man 7 backend" and "man 7 filter".
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU GENERAL PUBLIC LICENSE Version 2
# as published by the Free Software Foundation.
# Activate the "set -x" line to get debugging info in /var/log/cups/error_log:
#set -x
# Output "Device Discovery" information on stdout:
if test "$#" = "0"
then
echo 'direct pipe "Unknown" "Forward print job data like a pipe to another command"'
exit 0
fi
# Output usage information in case of wrong number of parameters:
if test "$#" != "5" -a "$#" != "6"
then
echo 'Usage: pipe job-id user title copies options [file]' 1>&2
echo 'Queue setup example:' 1>&2
echo 'lpadmin -p queue_name -v "pipe:/path/to/command?option1=value1&-option2&value2" -E' 1>&2
echo 'The command is called with the specified options as:' 1>&2
echo '/path/to/command option1=value1 -option2 value2' 1>&2
echo 'The original command line parameters (... job-id user ...)' 1>&2
echo 'are provided as environment variables PIPE_BACKEND_ARGV[0-6]' 1>&2
exit 1
fi
# Keep the original command line parameters (... job-id user ...)
# in environment variables to make them available for the command:
export PIPE_BACKEND_ARGV0="$0"
export PIPE_BACKEND_ARGV1="$1"
export PIPE_BACKEND_ARGV2="$2"
export PIPE_BACKEND_ARGV3="$3"
export PIPE_BACKEND_ARGV4="$4"
export PIPE_BACKEND_ARGV5="$5"
export PIPE_BACKEND_ARGV6="$6"
# Have the input at fd0 (stdin) in any case:
if test -n "$6"
then
exec <"$6"
fi
# To be on the safe side clip anything after the first space character
# because spaces are excluded characters in a URI (see RFC 2396):
URI=${DEVICE_URI%% *}
# Extract the command to which the job schould be sent from the URI.
# Clip the URI scheme (anything up to the first ':' character) and
# clip anything after the first '?' character
# because anything after the first '?' character are options:
COMMAND=${URI#*:}
COMMAND=${COMMAND%%\?*}
# Extract the options (e.g. from 'pipe:/path/to/command?option1=value1&-option2&value2'
# clip anything up to the first '?' character and
# replace the options separator '&' character by a space:
OPTIONS=${URI#*\?}
if test "$OPTIONS" = "$URI"
then
OPTIONS=""
fi
OPTIONS=$( echo "$OPTIONS" | tr '&' ' ' )
# Options could have been specified in a wrong way
# as addendum to the DeviceURI separated by spaces
# (spaces are excluded characters in a URI, see RFC 2396)
# which works by luck at least for some CUPS versions
# see https://bugzilla.novell.com/show_bug.cgi?id=499735
# like 'pipe:/path/to/command option1=value1 -option2 value2'
# nevertheless use additionally those kind of options too:
MORE_OPTIONS=${DEVICE_URI#* }
if test "$MORE_OPTIONS" = "$DEVICE_URI"
then
MORE_OPTIONS=""
fi
OPTIONS=$( echo "$OPTIONS" "$MORE_OPTIONS" | tr -s ' ' )
# Test if the command is executable:
if ! test -x "$COMMAND"
then
echo "Cannot execute $COMMAND" 1>&2
exit 1
fi
# Replace this wrapper with the actual command
# so that it exits with the exit code of the command
# and that the command gets any signals directly.
exec "$COMMAND" $OPTIONS
Como este é um script bash, você deve ser capaz de usá-lo com qualquer versão do 'nix, incluindo o Ubuntu, com um shell bash, não apenas Suse.
Para adicionar um backend aos cups, você precisará copiá-lo para /usr/lib/cups/backend e defina as permissões e a propriedade para corresponder.
chown root:root /usr/lib/cups/backend/pipe
chmod 755 /usr/lib/cups/backend/pipe
Fontes: