Problem running script

My requirement is to write a query in a file read the input from that file
run in postgresql and write the output(query results) into a file. I'm not
able to sue combination of \i and \o
Let' say I have file test.sql and in test.sql I write
select * from abc;

Now I need to read the query from the file and write the output to a file. I
tried
=>\i test.sql \o test

but this is not working. can any one tell me how to do this. I also need to
put my file in a place which can run the file at particualr time of the
day(like cron tab). Where do I put my file?

Regards,
sushma