/etc/oratab

The /etc/oratab file is a registry of installed databases and Oracle homes on a machine. The main purpose of this file is to automate

• setting environment variables
• starting and stopping Oracle databases (instances)

The file is created by $ORACLE_HOME/root.sh and updated by the

• Database Configuration Assistant (when a database is created) or
• ASM configuration assistant (when an ASM instance is created).

Each non empty line in this file is an entry.

Lines can be commented with #.

An entry consists of three parts that are separated by a colon (:)

• The first part is the Oracle SID.
• The second part is the path to the Oracle Home directory.
• The third part is either an N or a Y to indicate if the respective database should be started when the system is booted.

ora12c:/opt/Ora12/product/12.2.0/dbhome_1:N

$ cat /etc/oratab | awk -F: '{print $1}' | grep -v "#"