I would kindly request if somebody can brief me on this sftp script:

I have a regular ftp script;

HOST='ftp.server.com'
USER='RubinPat'
PASSWD='myname'
ftp -in $HOST <<END_SCRIPT
quote USER $USER
quote PASS $PASSWD

bi
get file.txt

Now my requirement is to create a sftp script. As per suggestion I created a .netrc file but that is not allowed. I have never done a sftp script before so am grooping in the dark. Can somebody tell me am I supposed to create a .ssh file or something....is sftp very much different than regular ftp as per coding is concerned........I tried the man page but there is no direction. Can somebody just write me the steps or guide me please? Thanks,