I have built an OSM tile server on Debian. I would like to know how could I see the map version? In fact, I would like to verify if the map data is updated. Thanks!
If you are running openstreetmap-tiles-update-expire, check /var/log/tile/run.log: it should contain results of each update. File /var/lib/mod_tile/.osmosis/state.txt should contain a timestamp of the last update.
The osm2pgsql database does not contain timestamps, so you cannot check whether you have the latest data. All you can do is map something from aerial imagery (please do not add bogus objects!), wait for couple minutes and check that changes were drawn on your tiles. To check tile update time, add /status to its URL: e.g. http://localhost/tiles/0/0/0.png/status. To force tile update, use /dirty instead, and wait.