Finding the init.ora file path from the location of an ifile is dangerous for a couple of reasons:

1) The database may or may not use an include file (specified using the ifile parameter in init.ora as mentioned in the previous post).

2) The include file (ifile) does not have to be in the same location as the init.ora file.

The init.ora file should be found under the Oracle home directory, in the dbs subdirector. Obviuosly, the specification of this path is operating-system specific.

HTH.

David.