how to save settings in sqlplus

Every time I start an sqlplus session I have to do a
set linesize 300 and a
format numbers col ....
and all.
Is there anyway I could make these changes permemant so that everytime I start a new sqlplus session, I dont have to make these changes manually.
Thanks.

There is a sql script called glogin.sql which will be in the place where you have the sqlplus.exe Just make those changes there and all those settings shall be executed everytime you invoke sqlplus