Even if an upgrade seems easy from the shown instructions, there are a quite a few factors that the DBA should bear in mind.
The database can be upgraded in several ways, one example is an imp/exp of GoldenGate Dataguard Transportable tablespace.
It is highly recommended going through the pdf slides available in https://blogs.oracle.com/upgrade/.
Log on to https://support.oracle.com/ with a username and password (provided by your organization) and download the 126.96.36.199 patch. Upgrade documentation can be found with the patchset. While transitioning to 11G it is possible to move the file system structure to the ASM (Automatic Storage Management) structure type.
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 – 64bit
PL/SQL Release 10.2.0.5.0 – Production
CORE 10.2.0.5.0 Production
TNS for Linux: Version 10.2.0.5.0 – Production
NLSRTL Version 10.2.0.5.0 – Production
As can be seen, the database is currently on version 10.2.0.5.0.
Download and unzip the following files from https://support.oracle.com
Note: The new oracle_home should be updated in /home/oracle/.bash_profile file.
Oracle Database 11g Enterprise Edition Release 188.8.131.52.0 – 64bit Production
PL/SQL Release 184.108.40.206.0 – Production
CORE 220.127.116.11.0 Production
TNS for Linux: Version 18.104.22.168.0 – Production
NLSRTL Version 22.214.171.124.0 – Production