strip_rfc_pagination

#! /bin/sh

# strip_rfc_pagination - strip pagination from RFCs and Internet-Drafts
# Copyright (C) 2019-2021  Erik Auerswald <auerswal@unix-ag.uni-kl.de>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Take the text of an RFC or Internet-Draft formatted with pagination
# (page header, page footer, form-feed control character).
#
# First, remove all page header and footer lines. Note that the first
# page does not have a header.
#
# Second, replace consecutive empty lines with a single empty line.
#
# The resulting text is well suited to be read with a common pager
# in the likes of more or less.
#
# Note that a page break inserted inside a paragraph of the input text
# leads to a spurious empty line in the output of this program.

sed -E \
 '/^(Internet-Draft|RFC[[:space:]]*[[:digit:]]+)([[:space:]]{3,}[^[:space:]].+[[:space:]]{3,}[^[:space:]]+)|\[[Pp]age[[:space:]]+[[:digit:]]+\]|\f/d' \
 -- "$@" \
| sed -E '/^$/{H;$!d};x;s/\n+/\n/'