How to use “/ as sysdba” to exp and imp

Sometimes we need to user “/ as sysdba” to do export and import in command line of operating systems. There is a little trick.
1. OS:Window 2000 Server
DB:Oracle9.2.0.1
exp userid=”””/ as sysdba””” tables=(t.t) file=t.dmp
imp userid=”””/ as sysdba””” file=t.dmp fromuser=t touser=system
Here three double quotation marks are used.
2.OS:SunOS 5.9
DB:Oracle9.2.0.5
exp userid=\’/ as sysdba\’ tables=(query_user.aaa) file=t.dmp rows=n
imp userid=\’/ as sysdba\’ fromuser=query_user [...]