| it automatically removes log files when they are no longer needed.
  *** IMPORTANT ***
  If you have an existing Nix installation, you must checkpoint the
  Nix database to prevent recent transactions from being undone.  Do
  the following:
  - optional: make a backup of $prefix/var/nix/db.
  - run `db_checkpoint' from Berkeley DB 4.1:
  
    $ db_checkpoint -h $prefix/var/nix/db -1
  - optional (?): run `db_recover' from Berkeley DB 4.1:
    $ db_recover -h $prefix/var/nix/db
  - remove $prefix/var/nix/db/log* and $prefix/var/nix/db/__db* | ||
|---|---|---|
| .. | ||
| Makefile.am | ||