### 4.1 Specifying Options

#### 4.1.1 At the Command Line

All options specified at the command line have the following basic format:

         --option[=value]

where the ``=`' can be replaced by whitespace.

Some options also have single letter abbreviations of the form:

         letter [optional_whitespace value]

Any non-ASCII characters are expected to be in the encoding specified by the current locale.

To reset an option to the default value, prefix the option with a ``reset-`' and don't specify a value.

##### 4.1.1.1 Value options

To specify a value option simply specify the option with its corresponding value. For example to set the filter mode to TeX use ``--mode=tex`'.

If a value option has a single letter shortcut simply specify the single letter shortcut with its corresponding value. For example to use a the accented version of the American English dictionary use ``-d en_US-w_accents`'.

##### 4.1.1.2 Boolean options

To enable a boolean option simply specify the option without any corresponding value, or prefix it with an ``enable-`'. For example to create a backup file use ``--backup`'. To disable a boolean option prefix the option name with a ``dont-`' or ``disable-`'. To avoid creating a backup file use ``--dont-backup`'. Boolean options can also be set directly like a value option where the value is either "true" or "false", for example ``--backup=true`'.

If a boolean option has a single letter abbreviation simply give the letter corresponding to either enabling or disabling the option without any corresponding value. For example, to consider run-together words valid use ``-C`' or to consider them invalid use ``-B`'

##### 4.1.1.3 List options

To add a value to the list, prefix the option name with an ``add-`' and then specify the value to add. For example, to add the URL filter use ``--add-filter url`'. To remove a value from a list option, prefix the option name with a ``rem-`' and then specify the value to remove. For example, to remove the URL filter use ``--rem-filter url`'. To remove all items from a list prefix the option name with a ``clear-`' without specify any value. For example, to remove all filters use ``--clear-filter`'.

A list option can also be set directly, in which case it will be set to a single value. To directly set a list option to multiple values prefix the option name with a ``lset-`' and separate each value with a ``:`'. For example, to use the URL and TeX filter use ``--lset-filter url:tex`'.

#### 4.1.2 Via a Configuration File

Aspell can also accept options via a personal or global configuration file. The exact files to used are specified by the options `per-conf` and `conf` respectively but the personal configuration file is normally `.aspell.conf` located in the `HOME` directory and the global one is normally `aspell.conf` which is located in the `etc` directory which is normally `/usr/etc` or `/usr/local/etc`. To find out the particular values for your particular system use `aspell dump config`.

Each line of the configuration file has the format:

         option [value]

There may be any number of spaces between the option and the value however it can only be spaces, i.e. there is no ``=`' between the option name and the value and there are no preceding ``--`' as used on the command line.

Comments may also be included by preceding them with a ``#`' as anything from a ``#`' to a newline is ignored. Blank lines are also allowed.

To include a literal ``#`' use ``\#`'. To include a literal ``\`' use ``\\`'. Any other non-alpha character can also be protected by a ``\`' if necessary.

Any non-ASCII characters are expected to be in UTF-8.

To reset an option to the default value prefix the option with a ``reset-`' and don't specify a value.

Values set in the personal configuration file override those in the global file. Options specified at either the command line or via an environment variable override those specified by either configuration file.

> Note: Filters and corresponding options also may be assembled inside a special meta filter file named `metafilter.flt`. A filter has to be loaded via adding a `add-filter` filtername line to the meta filter file before its options may be specified.

##### 4.1.2.1 Value options

To specify a value option simply include the option followed by the corresponding value. For example to set the default language to German use `lang german`.

##### 4.1.2.2 Boolean options

To specify a boolean option simply include the option followed by a ``true`' to enable it or a ``false`' to disable it. For example to allow run-together words use ``run-together true`'.

##### 4.1.2.3 List options

To add a value to the list, prefix the option name with an ``add-`' and then specify the value to add. For example to add the URL filter use ``add-filter url`'. To remove a value from a list option prefix the option name with a ``rem-`' and then specify the value to remove. For example, to remove the URL filter use ``rem-filter url`'. To remove all items from a list prefix the option name with a ``clear-`' without specifying any value. For example, to remove all filters use ``clear-filter`'.

A list option can also be set directly, in which case it will be set to a single value. To directly set a list option to multiple values prefix the option name with a ``lset-`' and separate each value with a ``:`'. For example, to use the URL and TeX filter use ``lset-filter url:tex`'. To include a literal ``:`' use ``\:`'.

#### 4.1.3 Setting Options via an Environment Variable

The environment variable `ASPELL_CONF` may also be used and it overrides any options set in the configuration file. The format of the string is exactly the same as the configuration file except that semicolons (``;`') are used instead of newlines.