Adapted Jonty's original solr.sh script to instead set up lucene full-text search in dovecot.

setup/lucene.sh

+#!/bin/bash
+# IMAP search with lucene
+# --------------------------------
+#
+# Adapted from https://github.com/Jonty/mailinabox/blob/solr_support/setup/solr.sh
+#
+# By default dovecot uses its own Squat search index that has awful performance
+# on large mailboxes. Dovecot 2.1+ has support for using Lucene internally but
+# this didn't make it into the Ubuntu packages, so we maintain our own
+# dovecot-lucene package in a ppa.
+
+source setup/functions.sh # load our functions
+source /etc/mailinabox.conf # load global vars
+
+# Install packages and basic configuation
+# ---------------------------------------
+
+# Add official ppa
+hide_output add-apt-repository -y ppa:brock/mailinabox-brocktice
+
+# Install packages
+apt_install dovecot-lucene
+
+# Update the dovecot plugin configuration
+#
+# Break-imap-search makes search work the way users expect, rather than the way
+# the IMAP specification expects
+tools/editconf.py /etc/dovecot/conf.d/10-mail.conf \
+        mail_plugins="$mail_plugins fts fts_lucene"
+
+cat > /etc/dovecot/conf.d/90-plugin.conf << EOF;
+plugin {
+  fts = lucene
+  fts_lucene = whitespace_chars=@.
+}
+EOF
+
+# PERMISSIONS
+
+# Ensure configuration files are owned by dovecot and not world readable.
+chown -R mail:dovecot /etc/dovecot
+chmod -R o-rwx /etc/dovecot
+
+# Restart services to reload solr schema & dovecot plugins
+restart_service dovecot