How to Identify Oracle 64 bit or 32 bit

Oracle Software is 32 bit or 64 bit.

Method 1:
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Go to $ORACLE_HOME/bin and see.

# cd $ORACLE_HOME/bin
# file oracle
oracle: ELF 64-bit LSB executable AMD64 Version 1, dynamically linked, not stripped

Here it comes 64 bit and hence oracle software is 64 bit. If the output of the "file oracle" command does not say 64-bit explicitly then you are running 32-bit Oracle.

If you had 32 bit oracle software installed then output will be like,

oracle@sol:/db/oracle/bin$ file oracle
oracle: setuid setgid ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), not stripped

Method 2:
----------------------
Log on to SQL*plus and see the banner.

-bash-3.00$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.2.0 - Production on Thu May 15 02:50:37 2008

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - Production
With the Partitioning, OLAP and Data Mining options

Method 3:Query from v$version.
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sys@THERAP> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - Prod
PL/SQL Release 10.2.0.2.0 - Production
CORE 10.2.0.2.0 Production
TNS for Solaris: Version 10.2.0.2.0 - Production
NLSRTL Version 10.2.0.2.0 - Production

Method 4: Check for lib, lib32
--------------------------------------

1) $ORACLE_HOME/lib32
2) $ORACLE_HOME/lib

If the two directories $ORACLE_HOME/lib32 and $ORACLE_HOME/lib are existing then it is 64 bit.

If there is only an ORACLE_HOME/lib directory then it is 32 bit client.