详细步骤：

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> quit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@localhost Desktop]$ cd 
[oracle@localhost ~]$ vim .bashrc
[oracle@localhost ~]$ cat .bashrc 
# .bashrc

# Source global definitions
if [ -f /etc/bashrc ]; then
    . /etc/bashrc
fi

# User specific aliases and functions
export ORACLE_SID=orcl_new #将实例名改为orcl_new
export ORACLE_BASE=/oracle/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/11.2.0/db_1
export LIBPATH=$ORACLE_HOME/lib
export
PATH=$ORACLE_HOME/bin:/bin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/X11R6/bin
umask 022
[oracle@localhost ~]$ source .bashrc 
[oracle@localhost ~]$ cd $ORACLE_HOME/dbs
[oracle@localhost dbs]$ ls -lrt
total 20
-rw-r--r--. 1 oracle oinstall 2851 May 15  2009 init.ora
-rw-r-----. 1 oracle oinstall   24 May 31 16:51 lkORCL
-rw-r-----. 1 oracle oinstall 1536 May 31 16:52 orapworcl
-rw-r-----. 1 oracle oinstall 2560 Jun  5 23:48 spfileorcl.ora
-rw-rw----. 1 oracle oinstall 1544 Jun  6 03:28 hc_orcl.dat
[oracle@localhost dbs]$ cp spfileorcl.ora spfileorcl_new.ora
[oracle@localhost dbs]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.3.0 Production on Wed Jun 6 03:37:10 2018

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup nomount;
ORACLE instance started.

Total System Global Area 1603411968 bytes
Fixed Size          2228784 bytes
Variable Size         939527632 bytes
Database Buffers      654311424 bytes
Redo Buffers            7344128 bytes
SQL> alter database mount;

Database altered.

SQL> select status from v$instance;

STATUS
------------
MOUNTED

SQL> alter database open;

Database altered.

SQL> select status from v$instance;

STATUS
------------
OPEN

SQL> show parameter name;

NAME                     TYPE    VALUE
------------------------------------ ----------- ------------------------------
db_file_name_convert             string
db_name                  string  orcl
db_unique_name               string  orcl
global_names                 boolean     FALSE
instance_name                string  orcl_new #实例名已改为orcl_new
lock_name_space              string
log_file_name_convert            string
processor_group_name             string
service_names                string  orcl
SQL> Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@localhost dbs]$ echo $ORACLE_SID
#实例名已改为orcl_new
orcl_new