Elektra: kdb(1) -- key database access tools

Elektra 0.8.24

kdb(1) -- key database access tools

Elektra provides a universal and secure framework to store configuration parameters in a global, hierarchical key database.

The core is a small library implemented in C. The plugin-based framework fulfills many configuration-related tasks to avoid any unnecessary code duplication across applications while it still allows the core to stay minimal without any external dependency. Elektra abstracts from cross-platform-related issues with a consistent API, and allows applications to be aware of other applications' configurations, leveraging easy application integration.

The man pages can also be viewed online at: https://doc.libelektra.org/api/current/html/pages.html

And the page you are currently reading at: https://doc.libelektra.org/api/current/html/md_doc_help_kdb.html

Concepts are in man page section 7 and are prefixed with `elektra-`. You should start reading elektra-introduction(7).

Tools are in man page section 1 and are prefixed with `kdb-`. You should start reading kdb-introduction(1).

Documentation of plugins is available using the kdb-info(1) tool. Run `kdb list` for a list of plugins.

## BASIC OPTIONS

Every core-tool has the following options:

- `-H`, `--help`: Show the man page.
- `-V`, `--version`: Print version info.
- `-p`, `--profile <profile>`: Use a different kdb profile, see below.
- `-C`, `--color <when>`: Print never/auto(default)/always colored output.
- `--`: Do not process any following arguments starting with `-` as options.

## COMMON OPTIONS

Most tools have the following options:

- `-v`, `--verbose`: Explain what is happening.
- `-q`, `--quiet`: Suppress non-error messages.

## KDB

The `kdb` utility reads its own configuration from three sources within the KDB (key database):

1. /sw/kdb/**profile**/ (for legacy configuration)
2. /sw/elektra/kdb/#0/%/ (for empty profile, `%` in Elektra is used to represent a emptiness)
3. /sw/elektra/kdb/#0/**profile**/ (for current profile, if no `-p` or `--profile` is given, `current` will be used)

Here the last source where a configuration value is found, wins.

For example, to permanently change verbosity one can use:

- `kdb set /sw/elektra/kdb/#0/current/verbose 1`: Be verbose for every tool.
- `kdb set /sw/elektra/kdb/#0/current/quiet 1`: Be quiet for every tool.

If `%` is passed to `-p` or `--profile`, the KDB will not be consulted for configuration and only the command-line arguments are used.

## PROFILES

Profiles allow users to change many/all configuration settings of a tool at once. It influences from where the KDB entries are read. Without a `-p` or `--profile` argument following profiles are used (in the order of preference):

- `current`: Is the profile to be used only if no `-p` argument was used.
- `%`: Is the fallback profile. It will be used if keys cannot be found in the main profile.

For example if you use:
`kdb export -p admin system`

It will read its format configuration from `/sw/elektra/kdb/#0/admin/format`.

If you want different configuration per user or directories, you should prefer to use the `user` and `dir` namespaces. Then the correct configuration will be chosen automatically according to the current user or current working directory.

Sometimes it is useful to start with default options, for example it is not possible to invert the `-q` option. In such situations one can simply select a non-existing profile, then `-q` works as usual:
`kdb mount -p nonexist -q /abc dir/abc`

If `%` is used as profile name for `-p`, the `kdb` tools disables reading from `KDB` for their own configuration settings. Then, they only use command-line arguments.

To explicitly state the default behavior, we use:
`-p current`

To state that we do not want to read any configuration settings for `kdb` from KDB, we use:
`-p %`

> Note that KDB will still be used to perform the actions you want to perform with the `kdb` tool.

## BOOKMARKS

Elektra recommends to use rather long paths because it ensures flexibility in the future (e.g. to use profiles and have a compatible path for new major versions of configuration).

Long paths are, however, cumbersome to enter in the CLI. Thus one can define bookmarks. Bookmarks are keys whose key name starts with `+`. They are only recognized by the `kdb` tool or tools that explicit have support for it. Your applications should not depend on the presence of a bookmark.

Bookmarks are stored below:
`/sw/elektra/kdb/#0/current/bookmarks`

For every key found there, a new bookmark will be introduced.

Bookmarks can be used to start key names by using `+` (plus) as first character. The string until the first `/` will be considered as bookmark.

For example, if you set the bookmark kdb:

        kdb set user/sw/elektra/kdb/#0/current/bookmarks
        kdb set user/sw/elektra/kdb/#0/current/bookmarks/kdb user/sw/elektra/kdb/#0/current

You are able to use:

        kdb ls +kdb/bookmarks
        kdb get +kdb/format

## RETURN VALUES

- 0: successful.
- 1: Invalid options passed.
- 2: Invalid arguments passed.
- 3: Command terminated unsuccessfully without specifying error code.
- 4: Unknown command.
- 5: KDB Error, could not read/write from/to KDB.
- 6: Reserved error code.
- 7: Unknown errors, wrong exceptions thrown.
- 8-10: Reserved error codes.
- 11-20: Command-specific error codes. See man page of specific command.

## SEE ALSO

- elektra-introduction(7)
- kdb-introduction(1)
- Get a big picture about Elektra