Just to clarify, the database that I wanted to check if it was Enterprise or Standard is dead, the disk array ate all the data files, so I can't run any SQL. All I had was the ORACLE_HOME directory. I recovered the database to a different server, from backups, which I know had Standard Edition because I installed it this morning.
The best way to check is to query v$version. The banners are not always reliable. select * from v$version; Pat