Enable and disable oracle in Linux

$ Su-Oracle switch to Oracle user first

1. Start Oracle
$ Sqlplus/nolog
SQL> Conn/As sysdba
SQL> startup (generally, you do not need to add parameters. You only need to set environment variables)
SQL> quit (exit SQL Mode)
$ LSNRCTL start (start listener) Close Oracle
$ LSNRCTL stop (close the listener. Close the application before that)

Ii. Disable Oracle
$ Sqlplus/nolog
SQL> shutdown: the shutdown parameter has four parameters. The meanings of the four parameters are as follows:
Normal: wait until all users are disconnected.
Immediate waits for the user to complete the current statement
Transactional waits for the user to complete the current transaction
Abort closes the database without waiting.
Normal requires that you close the database only after all connected users are disconnected. Sometimes it seems that the command is not running! New connections are not allowed after this command is executed.
Immediate disconnects the user after the user executes the statement being executed, and does not allow new users to connect.
Transactional disconnects after it supports executing the current transaction and does not allow new users to connect to the database.
Abort forcibly disconnects and closes the database.
The first three methods do not return lost user data. The fourth option is not recommended if it is no longer available!

Iii. FAQs
 

1) permission issues, solution, switch to Oracle user;

2) The Listener is not closed. Solution: Disable the listener.

3) If an oracle instance is not closed, the solution is to close the Oracle instance.

4) The environment variable settings are incomplete. Solution: Modify the environment variable.