diff --git a/manicito b/manicito
index f74edae..1bfa835 100755
--- a/manicito
+++ b/manicito
@@ -6,7 +6,41 @@
 # Date: 2024-04-10
 #―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――
 
-MANICITO_TEMPLATE='$USER (<a href="$USER_URL">$USERHOST</a>) <a href="$POST_URL">posted</a> about $TAG: <blockquote>$(echo "$POST" | head -c 200)</blockquote>'
+if test -z "$MANICITO_TEMPLATE"; then
+	MANICITO_TEMPLATE='$USER (<a href="$USER_URL">$USERHOST</a>) <a href="$POST_URL">posted</a> about $HASHTAG: <blockquote>$(echo "$POST" | head -c 200)</blockquote>'
+fi
+
+# Prints a simple usage message.
+usage() {
+	echo "usage: $(basename $0) [-h] [-H HISTORY_FILE] HASHTAG SERVER_URL"
+	echo 'Mastodon/Pleroma/etc script to quote-posts all posts of a given hashtag.'
+	echo
+	echo '  -h             print this message and exit'
+	echo '  -H             file used to store/check quoted posts; to avoid duplicates'
+	echo
+	echo 'Posts tagged under HASHTAG will all be quote-posted to the'
+	echo 'Mastodon-compatible server at SERVER_URL.'
+	echo
+	echo 'In order to make these posts, you must set the environment variable $FEDI_AUTH'
+	echo 'to your authorization token. To find your authorization token, you can snoop '
+	echo 'through request headers in your web-browser. In Firefox, you can do:'
+	echo '    Developer Tools (F12) → Network → Headers'
+	echo 'Look for your $FEDI_AUTH value in the Authorization header like so:'
+	echo '    Authorization: Bearer $FEDI_AUTH'
+	echo
+	echo 'To avoid duplicate-posts, you should specify a “history” file with the -H'
+	echo 'parameter. With this, all quoted post IDs will be saved in this file, and'
+	echo 'on subsequent runs (so long as you don’t change the history-file), no post'
+	echo 'will be quoted twice.'
+	echo
+	echo 'The environment variable $MANICITO_TEMPLATE is used create the body of your'
+	echo 'quote-posts. It substitutes the following shell-variables in templates:'
+	echo '   • $HASHTAG'
+	echo '   • $POST'
+	echo '   • $POST_URL'
+	echo '   • $USER'
+	echo '   • $USER_URL'
+}
 
 
 # Given a post’s JSON, create and submit a quote-post for it.
@@ -67,16 +101,28 @@ post_body() {
 #     echo $post_array_json | filter_posts $history_file
 filter_posts() {
 	local history_file="$1"
+	local ids_to_filter="$(history_post_ids "$history_file")"
 	# If the history file exists and has more than five characters, use it to filter… (sanity check)
-	if test -f "$history_file" -a "$(wc --bytes "$history_file" | awk '{print $1}')" -gt 5; then
+	if test -n "$ids_to_filter" -a "$(wc --bytes "$ids_to_filter" | awk '{print $1}')" -gt 5; then
 		jq -cr .[] \
-			| grep --invert-match $(sort "$history_file" | uniq | grep -v '^[[:space:]]*$' | sed 's%^%-e %')
+			| grep --invert-match $(echo "$ids_to_filter" | sed 's%^%-e %')
 	else
 		jq -cr .[]
 	fi
 }
 
 
+history_post_ids() {
+	local history_file="$1"
+	if test -f "$history_file"; then
+		sort -n "$history_file" \
+			| uniq \
+			| grep -v '^[[:space:]]*$' \
+			| awk '{ print $2 }'
+	fi
+}
+
+
 # Pipe in fediverse posts in JSON format; these will all be echoed into the given
 # “history file”, so that they can be filtered out and avoided on subsequent
 # runs.
@@ -86,8 +132,7 @@ update_filter() {
 	if test -f "$history_file"; then
 		jq -r '(.created_at + "\t" +  .id)' \
 			| sort -n \
-			| awk -F '\t' '{print $2}' \
-				  >> "$history_file"
+				   >> "$history_file"
 	fi
 }
 
@@ -115,8 +160,49 @@ env_subst() {
 }
 
 
-FEDI_SERVER="https://jam.xwx.moe"
-curl "$FEDI_SERVER/api/v1/timelines/tag/esperanto" \
-	| filter_posts "m" \
+
+while getopts 'hH:' arg; do
+	case $arg in
+		h)
+			usage
+			exit 0
+			;;
+		H)
+			HISTORY_FILE="$OPTARG"
+			;;
+	esac
+done
+
+shift $((OPTIND-1))
+HASHTAG="$1"
+FEDI_SERVER="$2"
+
+
+if test -z "$HASHTAG"; then
+	usage
+	exit 1
+fi
+
+if test -z "$FEDI_AUTH"; then
+	1>&2 echo 'You need to set the environment variable $FEDI_AUTH!'
+	1>&2 echo 'You can find your auth key by examining the "Authorization: Bearer" header'
+	1>&2 echo "used in requests by your server's web-client."
+    1>&2 echo 'In Firefox, F12→Network.'
+	1>&2 echo ""
+	exit 2
+fi
+
+if test -z "$FEDI_SERVER"; then
+	1>&2 echo 'No server specified!'
+	1>&2 echo 'Make sure to provide a hashtag (like #esperanto) and a'
+	1>&2 echo 'server URL (like https://fedi.server) as the last two arguments.'
+	1>&2 echo
+	1>&2 echo 'Run with -h for more information.'
+	exit 3
+fi
+
+
+curl "$FEDI_SERVER/api/v1/timelines/tag/$HASHTAG" \
+	| filter_posts "$HISTORY_FILE" \
 	| quote_posts \
-	| update_filter "m"
+	| update_filter "$HISTORY_FILE"