Usually TNS-01201 listener error pop up when oracle can’t find its executable under ORACLE_HOME variable mentioned in listener.ora file. After investigating listener.ora file, Found same, ORACLE_HOME was set to wrong path. After setting proper path listener started successfully.

Have a look on error logs:

Error Log: While starting listener

[oracle@PR admin]$ lsnrctl start
...
Starting /u01/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 11.2.0.1.0 - Production
System parameter file is /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/diag/tnslsnr/PR/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=PR.localdomain)(PORT=1521)))
TNS-01201: Listener cannot find executable /u01/oracle/product/11.2.0/dbhome_1/bin/oracle for SID RTS
Listener failed to start. See the error message(s) above...

Error Log: While tnsping

[oracle@PR admin]$ tnsping RTS
Used parameter files:
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = PR)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = RTS) (GLOBAL_NAME = RTS) (UR=A)))
TNS-12541: TNS:no listener

listener.ora file:

SID_LIST_LISTENER =
 (SID_LIST =
  (SID_DESC =
   (GLOBAL_DBNAME = RTS)
   (ORACLE_HOME = /u01/oracle/product/11.2.0/dbhome_1)
   (SID_NAME = RTS)
  )
 )
LISTENER =
 (DESCRIPTION =
  (ADDRESS = (PROTOCOL = TCP)(HOST = PR)(PORT = 1521))
 )
ADR_BASE_LISTENER = /u01/app/oracle

Solution:

Checkout above RED highlighted lines, mentioned ADR_BASE_LISTENER path is different then ORACLE_HOME. So after applying changes, listener started successfully. As follows:

[oracle@PR admin]$ lsnrctl start
Starting /u01/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait...
System parameter file is /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/diag/tnslsnr/PR/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=PR.localdomain)(PORT=1521)))
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=PR)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date 29-AUG-2015 09:22:35
Uptime 0 days 0 hr. 0 min. 0 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
Listener Log File /u01/app/oracle/diag/tnslsnr/PR/listener/alert/log.xml
Listening Endpoints Summary...
 (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=PR.localdomain)(PORT=1521)))
Services Summary...
Service "RTS" has 1 instance(s).
Instance "RTS", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully

tnsping also successful to RTS SID

[oracle@PR admin]$ tnsping RTS
Used parameter files:
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = PR)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = RTS) (GLOBAL_NAME = RTS) (UR=A)))
OK (0 msec)

Thanks,

Stay Tune. 🙂