$ echo $TWO_TASK
dbo_foobar
$ tnsping $TWO_TASK

TNS Ping Utility for Linux: Version 12.1.0.1.0 - Production on 03-SEP-2014 11:25:08

Copyright (c) 1997, 2013, Oracle.  All rights reserved.

Used parameter files:
/pro/oracle/v12.1/network/admin/sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact ( DESCRIPTION = ( ADDRESS_LIST = ( ADDRESS = ( HOST = dbo)( PORT = 1521)( PROTOCOL = TCP))) ( CONNECT_DATA = ( SERVICE_NAME = foobar)))
OK (150 msec)
$ env DBI_TRACE=1 perl -MDBI -wE'DBI->connect ("dbi:Oracle:", split m{/} => $ENV{ORACLE_USERID})'
    DBI 1.631-ithread default trace level set to 0x0/1 (pid 9871 pi 1eba010) at DBI.pm line 288 via -e line 0
    -> DBI->connect(dbi:Oracle:, USER, ****)
    -> DBI->install_driver(Oracle) for linux perl=5.020000 pid=9871 ruid=203 euid=203
       install_driver: DBD::Oracle version 1.74 loaded from /pro/lib/perl5/site_perl/5.20.0/x86_64-linux-thread-multi-ld/DBD/Oracle.pm
    <- STORE('ShowErrorStatement', 1)= ( 1 ) [1 items] at Oracle.pm line 81
    <- install_driver= DBI::dr=HASH(0x2045f30)
    <- connect('', 'USER', ...)= ( DBI::db=HASH(0x21ec3e8) ) [1 items] at DBI.pm line 671
    <- STORE('PrintError', 1)= ( 1 ) [1 items] at DBI.pm line 723
    <- STORE('AutoCommit', 1)= ( 1 ) [1 items] at DBI.pm line 723
    <- STORE('Username', 'USER')= ( 1 ) [1 items] at DBI.pm line 726
    <- connected('dbi:Oracle:', 'USER', ...)= ( undef ) [1 items] at DBI.pm line 733
    <- connect= DBI::db=HASH(0x21ec3e8)
    <- STORE('dbi_connect_closure', CODE(0x21ebde8))= ( 1 ) [1 items] at DBI.pm line 742
    <- DESTROY(DBI::db=HASH(0x21ec310))= ( undef ) [1 items] at -e line 1
    <- disconnect_all= ( ) [0 items] (not implemented) at DBI.pm line 750
!   <- DESTROY(DBI::dr=HASH(0x2045f30))= ( undef ) [1 items] during global destruction