Create a pfile from the spfile and vice versa

Command

-- spfile -> pfile (for backup/editing):
CREATE PFILE='/tmp/init_orcl_backup.ora' FROM SPFILE;

-- pfile -> spfile (make the edited pfile permanent; effective after restart):
CREATE SPFILE FROM PFILE='/tmp/init_orcl_backup.ora';

-- Create a pfile from the running instance values (11g+):
CREATE PFILE='/tmp/init_current.ora' FROM MEMORY;

What it does

Converts between the binary spfile and the text pfile; the pfile can be edited by hand.

When to use it

Backup before a parameter change, repairing a corrupt spfile, fixing a static parameter by hand.

Caution

After CREATE SPFILE FROM PFILE, changes take effect only after a restart. Verify the path before overwriting an existing spfile.