A customer of mine is running a different installation of Oracle(9)than I have seen. Usually I see SQL Developer installed, which is a GUI very similar to MS SQL Server Management Studio, but this customer doesn't seem to have that. I need to copy one database to another. Can I do that using SQL PLUS? Alternative method, Can I restore a database in SQL PLUS using a back up from another database? If so how exactly do I do that? What commands do I type?

Yes, you may use SQL Plus assuming you have an account with privileges on the source database. Have you tried Oracle's imp/exp command? The exp command will export the database to a flat file. Then you may use that exported file to do an import on your source server/pc.

You can also restore sql databases applying professional recovery tool

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