TNS-01201: Listener cannot find executable /u01/app/oracle/product/11.2.0/bin/oracle for SID RAC1

getting error while trying to start listener on rac node

TNS-01201: Listener cannot find executable /u01/app/oracle/product/11.2.0/bin/oracle for SID RAC1

[oracle@rac1 admin]$ lsnrctl start listener
LSNRCTL for Linux: Version 11.2.0.0 - Production
Copyright (c) 1991, 2013, Oracle.  All rights reserved.
Starting /u01/app/11.2.0/grid/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 11.2.0.0 - ProductionSystem parameter file is /u01/app/11.2.0/grid/network/admin/listener.oraLog messages written to /u01/app/oracle/diag/tnslsnr/rac1/listener/alert/log.xmlListening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))TNS-01201: Listener cannot find executable /u01/app/oracle/product/11.2.0/bin/oracle for SID RAC1
Listener failed to start. See the error message(s) above...
[oracle@rac1 admin]$ 

Looks like oracle can not find listener executable under ORACLE_HOME mentioned in listener.ora so had a look at the file and below was the content of the file

SID_LIST_LISTENER =(SID_LIST =        (SID_DESC =                (GLOBAL_DBNAME = RAC_DGMGRL.localdomain)                (ORACLE_HOME = /u01/app/oracle/product/11.2.0)                (SID_NAME = RAC1)   ) )

I have updated the listener.ora file with correct ORACLE_HOME and then tried starting the listener and all went well.

 SID_LIST_LISTENER = (SID_LIST =         (SID_DESC =                 (GLOBAL_DBNAME = RAC_DGMGRL.localdomain)                 (ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_1)                 (SID_NAME = RAC1)    ) )

[oracle@rac1 admin]$ lsnrctl start listener
LSNRCTL for Linux: Version 11.2.0.0 - Production 
Copyright (c) 1991, 2013, Oracle.  All rights reserved.
Starting /u01/app/11.2.0/grid/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 11.2.0.0 - ProductionSystem parameter file is /u01/app/11.2.0/grid/network/admin/listener.oraLog messages written to /u01/app/oracle/diag/tnslsnr/rac1/listener/alert/log.xmlListening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER)))STATUS of the LISTENER------------------------Alias                     listenerVersion                   TNSLSNR for Linux: Version 11.2.0.0 - ProductionStart Date                Uptime                    0 days 0 hr. 0 min. 0 secTrace Level               offSecurity                  ON: Local OS AuthenticationSNMP                      OFFListener Parameter File   /u01/app/11.2.0/grid/network/admin/listener.oraListener Log File         /u01/app/oracle/diag/tnslsnr/rac1/listener/alert/log.xmlListening Endpoints Summary...  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))Services Summary...Service "RAC_DGMGRL.localdomain" has 1 instance(s).  Instance "RAC1", status UNKNOWN, has 1 handler(s) for this service...The command completed successfully[oracle@rac1 admin]$