[To preserve all your settings create a file login.sql and save it in home direcory of Oracle.
1) edit login.sql -> File will be created in directory from where you are connecting
2) set your enviroment.
set lines 100
set pages 1000
set feedback 1
3) Save the file . If you save your file in local directory your settings will be in effect if you login from that direcory. To globalize your settings save your login.sql file in Home direcory of Oracle.