build script to create/update gh-pages branch

update-gh-pages-branch.sh

+#!/bin/bash
+#
+# This file is part of postpic.
+#
+# postpic 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.
+#
+# postpic 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 postpic. If not, see <http://www.gnu.org/licenses/>.
+#
+# Copyright Stephan Kuschel, 2020
+
+# This script creates the documentation as html and saves it to the
+# "gh-pages" branch.
+
+set -eux
+
+# ensure Working Directory is clean
+git diff-index --quiet HEAD
+
+if ! git rev-parse --verify --quiet gh-pages; then
+  current_branch=$(git branch --show-current)
+  echo 'create empty and orphan gh-pages branch'
+  git checkout --orphan gh-pages
+  git reset
+  git commit --allow-empty --no-verify -m "init empty gh-pages branch"
+  git checkout -f $current_branch
+fi
+
+# assert that Working Directory is still clean
+git diff-index --quiet HEAD
+SHA=$(git rev-parse --verify HEAD)
+
+# create documentation on gh-pages branch
+rm -rf doc/build/html
+git worktree add -f doc/build/html gh-pages
+cd doc
+make html
+cd build/html
+touch .nojekyll
+git add .
+git commit -a --no-verify -m "postpic documentation at $SHA"
+
+
+
+