How do you call the last log of ltm left by irule from icall?

sys icall script null { app-service none definition { } description none events none } sys icall script blacklist_ip_generation { app-service none definition { set blacklist_ip set a [lindex [exec tail -1 /var/log/ltm] 9 ] tmsh::modify "ltm data-group internal URL_Access_Black_IP records add { $blacklist_ip }" tmsh::log "$blacklist_ip is blacklist ip registration" } description none events none } sys icall handler triggered blacklist_ip_generation { script blacklist_ip_generation subscriptions { blacklist_ip_generation { event-name blacklist_ip_generation } } }