As mentioned above, the OS Path variable is automatically converted by Nushell. As a result, it can be treated as a list within your startup config without needing to be present in `ENV_CONVERSIONS`. Other colon-separated paths, like `XDG_DATA_DIRS`, are not automatically converted.
:::

To add an additional conversion, [`merge`](/commands/docs/merge.md) it into the `$env.ENV_CONVERSIONS` record. For example, to add a conversion for the `XDG_DATA_DIRS` variable:

```nu
$env.ENV_CONVERSIONS = $env.ENV_CONVERSIONS | merge {
    "XDG_DATA_DIRS": {
        from_string: {|s| $s | split row (char esep) | path expand --no-symlink }
        to_string: {|v| $v | path expand --no-symlink | str join (char esep) }
    }
}
```

### `LS_COLORS`

As with many `ls`-like utilities, Nushell's directory listings make use of the `LS_COLORS` environment variable for defining styles/colors to apply to certain file types and patterns.

## Nushell Settings in the `$env.config` Record

### Changing Settings in the `$env.config` Record

The primary mechanism for changing Nushell's behavior is the `$env.config` record. While this record is accessed as an environment variable, unlike most other variables it is:

- Not inherited from the parent process. Instead, it is populated by Nushell itself with certain defaults.
- Not exported to child processes started by Nushell.

To examine the current settings in `$env.config`, just type the variable name:

```nu
$env.config
```

::: tip
Since Nushell provides so many customization options, it may be better to send this to a pager like:

```nu
$env.config | table -e | less -R
# or, if bat is installed:
$env.config | table -e | bat -p
```

:::

An appendix documenting each setting will be available soon. In the meantime, abbreviated documentation on each setting can be viewed in Nushell using:

```nu
config nu --doc | nu-highlight | bat
# or
config nu --doc | nu-highlight | less -R
```

To avoid overwriting existing settings, it's best to simply assign updated values to the desired configuration keys, rather than the entire `config` record. In other words:

::: warning Wrong

```nu
$env.config = {
  show_banner: false
}
```

This would reset any _other_ settings that had been changed, since the entire record would be overwritten.
:::

::: tip Right

```nu
$env.config.show_banner = false
```

This changes _only_ the `show_banner` key/value pair, leaving all other keys with their existing values.
:::

Certain keys are themselves also records. It's okay to overwrite these records, but it's best-practice
to set all values when doing so. For example:

```nu
$env.config.history = {
  file_format: sqlite
  max_size: 1_000_000
  sync_on_enter: true
  isolation: true
}
```

### Remove Welcome Message

:::note
This section is linked directly from the banner message, so it repeats some information from above.
:::

To remove the welcome message that displays each time Nushell starts:

1. Type `config nu` to edit your configuration file.
2. If you receive an error regarding the editor not being defined:

   ```nu
   $env.config.buffer_editor = <path to your preferred editor>
   # Such as:
   $env.config.buffer_editor = "code"
   $env.config.buffer_editor = "vi"
   # Or with editor arguments:
   $env.config.buffer_editor = ["emacsclient", "-s", "light", "-t"]
   ```

   Then repeat step 1.

3. Add the following line to the end of the file:

   ```nu
   $env.config.show_banner = false
   ```

4. Save and exit your editor.
5. Restart Nushell to test the change.

## Additional Startup Configuration

### Changing default directories

::: warning Important
As discussed below, variables in this section must be set **before** Nushell is launched.
:::

Some variables that control Nushell startup file locations must be set **before** Nushell is loaded. This is often done by a parent process such as:

- The terminal application in which Nushell is run

- The operating system or window manager. When running Nushell as a login shell, this will likely be the only mechanism available.