Oracle environment variables and identifiers that you don't pay much attention to, and oracle environment variables

Oracle environment variables and identifiers that you don't pay much attention to, and oracle environment variables
Sign (?) Represents the ORACLE_HOME Environment Variable
Eg:
SQL> ALTER TABLESPACE TEMP ADD DATAFILE '? /Dbs/temp02.dbf 'size 200 M;


Sign (@) represents the ORACLE_SID environment variable
Eg:
SQL> ALTER TABLESPACE tablespace_name ADD DATAFILE tempfile @. dbf


------ Oracle software running environment variables
-- ORACLE_TRACE tracks shell script execution during installation. The principle is to set-x implicitly.


ORACLE_TRACE = T enable shell Tracing
ORACLE_TRACE = if it is set to null, no trace is performed.


-- TNS_ADMIN oracle net service configuration file, it seems that many people do not know this variable. Sometimes the listening management exception means that this variable is not properly set,
Eg:

TNS_ADMIN = $ ORACLE_HOME/network/admin



-- TWO_TASK specifies the default connection ID (which must be configured in tnsnames. ora). If this variable is set, you can quickly connect to the database:

TWO_TASK = lixora

SQL> CONNECT lixora
Enter password: lixora


---------- Unix environment variables
-- CLASSPATH Used with Java applications

CLASSPATH = $ ORACLE_HOME/JRE/lib: $ ORACLE_HOME/jlib/* no default settings. The following settings must be included */

-- PATH Used by the shell to locate executable programs; shel uses this variable to determine the executable program
Eg:
PATH =/bin:/usr/local/bin:/usr/bin/X11: $ ORACLE_HOME/bin: $ HOME/bin: