I had a file with name "dump_live"
which contains all the dump using "pg_dumpall > dump_live". Now,
I need to restore it to another schema "schema2". How can I restore
the data from that file to specified empty schema2. (This schema is created
with out any objects). Pls advice me how to handle.
You dumped the entire database cluster...data, schema definitions, user/group data, etc. You're going to have to specify options for dumping and restoring data to do what you wish. This is well-documented in the list archives, the website, man pages, and many, many other places. Please read them.