You can verify Replication Server thread status using these commands:
admin who – provides information on all Replication Server threads
admin who_is_up or admin who_is_down – lists Replication Server threads that are running, or not running.
sp_help_rep_agent – provides information on the RepAgent thread and the RepAgent User thread.
See Chapter 1, “Verifying and Monitoring Replication Server” for more information about monitoring thread status.