In most instances of Netscout/Arbor servers I've seen, you'll be dropped into the ArbOS shell by default.
Some commands are unique to the service being run on that device (e.i. Sightline Leader, Collector, TMS).
Check for status alerts (from bash)
statusdump -aCheck logs for tadpole process - flow ingestion to Insight
tail -f /base/var/log/syslog | grep tadpoleSystem logs as shown in the ArbOS CLI are located at /base/data/diagtmp/DiagFile-<host-name>-PDCK