BRLTTY(1)

NAME
brltty - refreshable braille display driver for Linux/Unix

SYNOPSIS
brltty [option ...]

DESCRIPTION
brltty is a background process (daemon) which provides access to the Linux/Unix console (when in text mode) for a blind person using a refreshable braille display. It drives the braille display, and provides complete screen review functionality. Some speech capability has also been incorporated.

Parameters can be passed to brltty in a number of ways. From most to least influential, these are:

1   command line options

2   boot parameters

3   environment variables (if the -E (--environment-variables) option is in effect)

4   the configuration file

5   built-in defaults

  Command Line Options
The options are processed sequentially from left to right. If an option is specified more than once, or in case of a conflict, the rightmost specification takes precedence.

The supported options are:

-a table (--attributes-table=)
    The path to the attributes translation table. Relative paths are anchored at /etc/brltty/. The .tbl extension is optional. The built-in default is attributes.tbl.

-b driver (--braille-driver=)
    The driver for the braille display is a two-letter driver identification code. The built-in default is the driver which was configured in at build-time.

-c table (--contraction-table=)
    The path to the contraction table. Relative paths are anchored at /etc/brltty/. The .ctb extension is optional.

-d device (--braille-device=)
    The path to the device for accessing the braille display. Relative paths are anchored at /dev/. The built-in default is the first serial port.

-e (--standard-error)
    Write logs to standard error rather than to the system log (useful for debugging).

-f file (--configuration-file=)
    The full path to the configuration file. The built-in default is /etc/brltty.conf.

-h (--help)
    Print a command line usage summary and exit.

-l level (--log-level=)
    The minimum severity level for messages written to the log. Any of the following numbers, or any abbreviation of their corresponding names, may be specified:

    0   emergency

    1   alert

    2   critical

    3   error

    4   warning

    5   notice

    6   information

    7   debug

The built-in default is notice.

-n (--no-daemon)
    Remain in the foreground (useful for debugging).

-p file (--preferences-file=)
    The full path to the preferences file. The built-in default is /etc/brltty-driver.prefs (where driver is the two-letter driver identification code).

-q (--quiet)
    Suppress start-up messages. The default log level (see the -l (--log-level=) option) is changed to warning (information if -v (--version) is also specified).

-s driver (--speech-driver=)
    The driver for the speech synthesizer is a two-letter driver identification code. The built-in default is the driver which was configured in at build-time.

-t table (--text-table=)
    The path to the text translation table. Relative paths are anchored at /etc/brltty/. The .tbl extension is optional. For a simple file name, the text. prefix is optional. The built-in default is text.nabcc.tbl.

-v (--version)
    Print start-up messages and exit. The default log level (see the -l (--log-level=) option) is changed to information.

-A name=value,... (--api-parameters=)
    Specify parameters for the application programming interface.

-B name=value,... (--braille-parameters=)
    Specify parameters for the braille display driver.

-E (--environment-variables)
    Recognize environment variables.

-M csecs (--message-delay=)
    The message hold time in hundredths of a second. The built-in default is 400 (4 seconds).

-N (--no-speech)
    Do not automatically start the speech synthesizer driver. It can still be manually started with the restart speech command at any time. This option should only be used if brltty is started before the sound subsystem of the kernel is initialized and problems with sound are encountered.

-P file (--pid-file=)
    The full path to the process identifier file. If this option is supplied, brltty writes its process identifier (pid) into the specified file on start-up.

-R csecs (--refresh-interval=)
    The braille window refresh interval in hundredths of a second. The built-in default is 4 (25 times per second).

-S name=value,... (--speech-parameters=)
    Specify parameters for the speech synthesizer driver.

-X name=value,... (--screen-parameters=)
    Specify parameters for the screen driver.

  Environment Variables
The following environment variables are recognized if the -E (--environment-variables) option is in effect:

BRLTTY_API_PARAMETERS=name=value,...
    Specify parameters for the application programming interface.

BRLTTY_ATTRIBUTES_TABLE=table
    The path to the attributes translation table. Relative paths are anchored at /etc/brltty/. The .tbl extension is optional.

BRLTTY_BRAILLE_DEVICE=device
    The path to the device for accessing the braille display. Relative paths are anchored at /dev/.

BRLTTY_BRAILLE_DRIVER=driver
    The driver for the braille display as either a two-letter driver identification code or the full path to the shared object.

BRLTTY_BRAILLE_PARAMETERS=name=value,...
    Specify parameters for the braille display driver.

BRLTTY_CONFIGURATION_FILE=file
    The full path to the configuration file.

BRLTTY_CCONTRACTION_TABLE=table
    The path to the contraction table. Relative paths are anchored at /etc/brltty/. The .ctb extension is optional.

BRLTTY_PREFERENCES_FILE=file
    The full path to the preferences file.

BRLTTY_SCREEN_PARAMETERS=name=value,...
    Specify parameters for the screen driver.

BRLTTY_SPEECH_DRIVER=driver
    The driver for the speech synthesizer as either a two-letter driver identification code or the full path to the shared object.

BRLTTY_SPEECH_PARAMETERS=name=value,...
    Specify parameters for the speech synthesizer driver.

BRLTTY_TEXT_TABLE=table
    The path to the text translation table. Relative paths are anchored at /etc/brltty/. The .tbl extension is optional. For simple file names, the text. prefix is optional.

  Configuration File
Blank lines are ignored. If the character # occurs on any line then all characters from it to the end of that line are treated as a comment.

The following configuration directives are supported:

api-parameters name=value,...
    Specify parameters for the application programming interface.

attributes-table table
    The path to the attributes translation table. Relative paths are anchored at /etc/brltty/. The .tbl extension is optional.

braille-device device
    The path to the device for accessing the braille display. Relative paths are anchored at /dev/.

braille-driver driver
    The driver for the braille display as either a two-letter driver identification code or the full path to the shared object.

braille-parameters name=value,...
    Specify parameters for the braille display driver.

ccontraction-table table
    The path to the contraction table. Relative paths are anchored at /etc/brltty/. The .ctb extension is optional.

preferences-file file
    The full path to the preferences file.

screen-parameters name=value,...
    Specify parameters for the screen driver.

speech-driver driver
    The driver for the speech synthesizer as either a two-letter driver identification code or the full path to the shared object.

speech-parameters name=value,...
    Specify parameters for the speech synthesizer driver.

text-table table
    The path to the text translation table. Relative paths are anchored at /etc/brltty/. The .tbl extension is optional. For simple file names, the text. prefix is optional.

SEE ALSO
For full documentation, see the on-line manual at [http://mielke.cc/brltty/doc/Manual-HTML/Manual.html].