怎样修改Oracle 下的SID

Oracle用户adm和ora。

怎样修改下面变量的oraSID（把所有的P35修改成T35）

p35test:orat35 1> env

TERM=vt100

AUTHSTATE=files

SHELL=/usr/bin/csh

HOME=/oracle/T35

USER=orat35

PATH=/oracle/P35/920_64/bin:/oracle/T35:/usr/sap/P35/SYS/exe/run:/usr/bin:/etc:/usr/sbin:/usr/ucb:/oracle/T35/bin:/usr/bin/X11:/sbin:.

TZ=BEIST-8

LANG=en_US

LOCPATH=/usr/lib/nls/loc

LC__FASTMSG=true

ODMDIR=/etc/objrepos

LOGNAME=orat35

LOGIN=orat35

SAPSYSTEMNAME=P35

DIR_LIBRARY=/usr/sap/P35/SYS/exe/run

THREAD=NOPS

dbms_type=ORA

dbs_ora_tnsname=P35

dbs_ora_schema=SAPR3

ORACLE_PSRV=P35

ORACLE_SID=P35

ORACLE_HOME=/oracle/P35/920_64

ORACLE_BASE=/oracle

ORA_NLS=/oracle/P35/920_64/ocommon/NLS_723/admin/data

ORA_NLS32=/oracle/P35/920_64/ocommon/NLS_733/admin/data

ORA_NLS33=/oracle/P35/920_64/ocommon/nls/admin/data

NLS_LANG=AMERICAN_AMERICA.WE8DEC

SAPDATA_HOME=/oracle/P35

MAIL=/var/spool/mail/orat35

MAILMSG=[YOU HAVE NEW MAIL]

NLSPATH=/usr/lib/nls/msg/%L/%N:/usr/lib/nls/msg/%L/%N.cat

LIBPATH=/usr/lib:/lib:/usr/sap/P35/SYS/exe/run:/oracle/P35/920_64/lib64