[oracle@usha ~]$ adrci

ADRCI: Release 11.2.0.1.0 - Production on Sat Feb 4 03:36:29 2012

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

ADR base = "/u01/app/oracle"
adrci> help

 HELP [topic]
   Available Topics:
        CREATE REPORT
        ECHO
        EXIT
        HELP
        HOST
        IPS
        PURGE
        RUN
        SET BASE
        SET BROWSER
        SET CONTROL
        SET ECHO
        SET EDITOR
        SET HOMES | HOME | HOMEPATH
        SET TERMOUT
        SHOW ALERT
        SHOW BASE
        SHOW CONTROL
        SHOW HM_RUN
        SHOW HOMES | HOME | HOMEPATH
        SHOW INCDIR
        SHOW INCIDENT
        SHOW PROBLEM
        SHOW REPORT
        SHOW TRACEFILE
        SPOOL

 There are other commands intended to be used directly by Oracle, type
 "HELP EXTENDED" to see the list

adrci> show homes
ADR Homes:
diag/tnslsnr/usha/listener
diag/rdbms/testdb/DB11G
diag/rdbms/testdb/testdb
adrci>