Linux Start Stop Oracle instance + How to start multiple instances __java

Start the database instance in two steps:
The first step, start listening;
[Oracle@wuzhq ~]$ su-oracle--"Switch to Oracle User"
[Oracle@wuzhq ~]$ lsnrctl Start--"turn on Listening"
The second step is to start the database instance.
[Oracle@wuzhq ~]$ Sqlplus/nolog--"Go to Sqlplus"
Sql> conn/as SYSDBA--"Connect to SYSDBA"
Sql> Startup--"Start database instance"
To close a database instance:
sql> shutdown Immediate--"Close database instance"
Sql> exit

[Oracle@redhat ~]$ Lsnrctl Stop

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If you have DB1 and DB2 two instances on your server, and these two instances are created by the same operating system user, log on to the server with this operating system user and Execute
Export ORACLE_SID=DB1
Sqlplus/nolog
Connect/as SYSDBA
Startup
Exit
Eof
Export ORACLE_SID=DB2
Sqlplus/nolog
Connect/as SYSDBA
Startup
Exit

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Sqlplus/as SYSDBA
startuppfile= $ORACLE _home/dbs/initdb1.ora
Exit

Sqlplus/as SYSDBA
startuppfile= $ORACLE _home/dbs/initdb2.ora
Exit