Add "version" action

CHANGELOG

@@ -9,6 +9,7 @@ and this project **does not adhere to [Semantic Versioning](http://semver.org/sp
 * store and compare state between restart
 * colorize output if terminal supports colors
 * simple syslog logging
+* "version" action
 
 ### Changed
 

minifirewall

@@ -1033,10 +1033,21 @@ reset() {
     syslog_info "reset"
     printf "${GREEN}${BOLD}${NAME} reset${RESET}\n"
 }
+show_version() {
+    cat <<END
+${NAME} version ${VERSION}
+
+Copyright 2007-2022 Evolix <info@evolix.fr>.
+
+${NAME} comes with ABSOLUTELY NO WARRANTY.
+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.
+END
+}
 
-echo "${NAME} version ${VERSION}"
 source_configuration
-
 check_unpersisted_state
 
 case "${1:-''}" in
@@ -1061,8 +1072,12 @@ case "${1:-''}" in
         start
     ;;
 
+    version)
+        show_version
+    ;;
+
     *)
-        echo "Usage: $0 {start|stop|restart|status|reset}" 
+        echo "Usage: $0 {start|stop|restart|status|reset|version}" 
         exit 1
     ;;
 esac