zdbr is used to remove records from a database. The records
to be removed are specified by their keys and are entered via
stdin or, optionally, they are read from a text file. If many
records are removed from the database, some fragmentation can occur.
In this case, it is advisable to reorganize the database, which is
possible via the --reorganize option.
In addition to the database file to be used and the common options,
zdbf command accepts the following options:
Read queries from a file instead of from stdin.
Reorganize the database.
Automatically synchronize all database operations to the disk.