Provided by: gom_0.30.2-6build1_amd64 
NAME
gom - a generic audio mixer (supports: OSS and derivatives)
SYNOPSIS
gom {OPTION}
VERSION
This manual page was distributed with gom 0.30.2 (31 May 2004).
DESCRIPTION
gom is a command line mixer manipulation program including a minimal, yet fully functional internal
ineractive text based interface.
Currently, there is also an internal X (xview) interface, but it's not well maintained and will
eventually be removed when a proper alternative is available.
At the moment, gom only supports the Open Sound System (OSS) and its derivatives (OSS/Lite, OSS/Free
(these two are obviously obsolete), the new Linux Sounddriver, ...).
gom tries to provide a complete and convenient interface for all kind of audio mixer manipulation. gom's
facilities include sound driver (compile time) and sound card (run time) independence, arbitrary mixer
selection, loading and saving of mixer settings, volume fading, verbosity-level driven output, "Un*x-like
scripting support", etc.
Apart from the exhaustive command line interface described here, gom has a built-in interactive terminal
interface (that I call gomii, gom interactive interface) using ncurses. It supports adjustable (this
includes disabling) real time updating. The gomii is not explained in this manual page; please refer to
the specific online help when using it. However, the gomii's handling should be obvious, and actually it
"tries to resemble" the command line options.
There is also one more gomii for X using the xview toolkit. However, gom needs to be especially compiled
to include this, and it is intended to be replaced eventually by some frontend for X using the gom
binary.
And remember: gom is spelled g-o-m, but pronounced backwards for compatibility reasons. Its real, actual
and recursive title is gom, GOM is nOt yet another Mixer (for reasons beyond the scope of this manual).
CONFIGURING GOM
There is no mandatory configuration for gom; it runs fine just as it is, without any configuration. I.e.,
for senseful use without configuration, one always needs to (at least) specify the mixer to use. For
example:
gom --device=/dev/mixer2 --mute-all
However, you can configure gom a) for the system and b) for an individual user; each user configuration
is preferred in favor of the corresponding system configuration. In fact, the routine for loading _any_
option file is to 1st try the user file, then the system file, and else fail.
To configure, you should use the script gomconfig(8) (or most likely gomconfig --force ) that comes with
the distribution -- using it as root will change the system configuration, normal users will change their
own configuration. You may well skip the rest of this chapter if you do so.
All configuration files for gom are simply gatherings of command line options to gom (where some files
are restricted to certain options). Please see "--get-options" below.
The configuration files are (replace the "~/.gom" with "/etc/gom" for the system configuration):
~/.gom/conf.default_mixer
Loaded on every startup of gom. Restricted to: "-d". Provides implicit opening of a mixer device.
~/.gom/conf.initialize
Loaded with the option '-O, --originate, --initialize'. Unrestricted. Provides creation of an
initialization routine, even for multiple mixers.
~/.gom/conf.gom
Loaded on every startup of gom. Restricted to '-v, -q, -F, -U'. Provides implicit creation of
certain bevaviours. Discouraged.
~/.gom/<mixer-device>.<name>
These file are accessed simply by their <name> when <mixer-device> is opened. See --get-options
below.
TERMINOLOGY, PHILOSOPHY
A mixer is a set of channels (e.g. vol, line, cd). Each channel has a set of volume channels (e.g. left,
right), and optionally a recording source flag.
The evaluation which channels are available, and, for an available channel, which volume channels and
which flags are available on that specific channel, is being done at runtime; this is sound card, and
possibly sound driver dependent.
Thus, there are sound driver supported channels and specific sound card supported channels. gom --info-
all shows all sound driver supported channels, plus indicating their specific availability.
Up to the time of this writing, the only sound driver supported is OSS (Open Sound System) and its
derivatives. This driver exists for a variety of platforms and in various flavours (especially, the new
Sounddriver of Linux is a derivative of OSS). (Remark: Gom's point of view on how a "generic" mixer
should look like may be strongly influenced by the OSS API; however, the author feels that this view
might not (yet) be absolutely generic). At the time of this writing, OSS supports 17 channels, and a
maximum of two volume channels per channel (i.e., only "mono" or "stereo").
Of course, as gom depends on the sound driver installed on the system, its proper installation (which is
naturally not covered here) is mandatory for gom (as for any other sound-using program).
OPTIONS
Options can be given in arbitrary order or amount; they are computed in sequence from left to right.
Default values (if any), are given in []. For boolean arguments, "1" means on, "0" means off.
Note that for options with _optional_ arguments, these must be gi ven like "gom -G<file>" (or "gom --get-
settings=<file>" resp.) ra ther than "gom -G <file>" (or "gom --get-settings <file>" resp.). Otherwise,
they will be ignored (or, at least with my implementat ion of getopt;).
Configuring options:
-d, --device, --mixer <argument>
[ **no mixer** ] Set mixer special device file to <argument>. If the new mixer is valid, the
current mixer --if any-- will be closed and the new mixer opened. Current channel, current channel
volume, the channel lock setting and the snapshot will be resetted to defaults.
-c, --channel <argument>
[first available channel] Set current mixer channel to <argum ent>. The channel may be given as
number or as name.
-C, --volume-channel <argument>
[first available volume channel on current channel] Set volum e channel on current mixer channel
to <argument> (e.g., for s tereo, 0 means left, 1 means right volume).
-k, --lock <argument>
-K, --lock-all <argument>
[1] Lock or unlock current or all channel(s). Locking means s yncing of the stereo volumes
(balance) for all volume setting s gom might do -- this doesn't change any volume settings by
itself (i.e., it doesn't auto-balance). Thus, a locked channe l might have unbalanced volumes.
-F, --fade-interval <argument>
[5] Set fade interval to <argument> seconds. See --fade-to-lo udness.
-U, --refresh-interval <argument>
[30] Set gomii refresh (update) interval to <argument> second s (zero disables).
-W, --write-config, --save-config
This option is obsolete since version 0.29.10.
Setting mixer options:
-l, --loudness, --volume <argument>
Set current volume channel on current channel to <argument>. If the argument is being given with
a leading "+" or "-", the given value will be added or substracted, respectively, from the current
value. The allowed range is from zero up to a sou ndcard driver dependent maximum.
-r, --record <argument>
Set recording for current channel on or off.
-R, --record-single
Set recording for current channel on and disable all other re cording sources.
-L, --fade-to-loudness, --fade-to-volume <argument>
Like --loudness, but fade to the new volume within a time giv en with --fade-interval.
-m, --mute
-M, --mute-all
Mute current or all channels. Muting means setting all channe l volumes to 0.
Mixer settings options:
-G, --get-options, --load-options, --get-settings, --load-setting
Get options from/to file <argument>. If no argument is given, the default file (named "default")
is used. Non-absolut given filenames will be expanded to "<mixer-device>.<argument>", and then
first searched for in the user and -- if this fails -- in the system configuration directory. Any
free-form files with gom one-character command line options in any lines starting with a dash (in
column zero) will make sense to this option.
-S, --save-settings [<argument>]
Save mixer settings to a free-form option file; for the file name, the same rules as for loading
option files apply, except that only the user configuration dir will be used. Files with thusly
expanded filenames will be silently overwritten; other files never. When saving, care is being
taken that the "last recording source error" can't occur when loading these options (and maybe
there are other reasonable side effects apart from the pure mixer settings (e.g. channel locking,
current channel)). The bottom line to these load/save options is that you can easily save new and
load predefined mixer settings from anywhere.
-z, --snapshot-settings
-Z, --unsnapshot-settings, --restore-settings
[mixer settings after opening a new mixer] Snap- or unsnapsho t to/from current mixer settings.
-O, --originate, --initialize
Load the options file "initialize"; all options are allowed in this file. This is meant to
initialize mixers. For example: "-d/dev/mixer0 -G -d/dev/mixer1 -G". This would load the default
settings file for both the mixer0 and the mixer1 device.
Informational options:
-t, --info
Display current channel information.
-T, --info-all
Display overall information.
-V, --version
Display version information.
-w, --copyright, --copyleft, --license, --warranty
Display copyright/license/warranty information.
-h, --help
-H, --help-verbose
Display this help normally or verbose; both helps are still d ependent on the current verbosity
level (i.e., higher verbosi ty levels might still show more; "gom -v0 -H" and "gom -h" pr oduce
the same output). For the normal verbosity level, these are reasonable macros.
Special options:
-e, --execute <argument>
Execute the shell command <argument>.
Command line only options:
-Y, --ignore-config
Skip all automatically loaded configurations files; this must be given before any other option
(except q (quiet) or v (verbose)).
-i, --interface, --gomii <argument>
Explicitly start up a build-in gomii (<argument>=t: terminal gomii, <argument>=x: X gomii).
-v, --verbose [<argument>]
[NORMAL] Set output verbosity to <argument> (number, the high er, the more verbose). If no
argument is given, the level will be increased by 1.
-q, --quiet, --silent
Set output verbosity to QUIET (only error / error help messag es).
-p, --pure, --print <argument>
Pure-print the current channels value given by <argument> to stdout (<argument>=l|r, according to
one character options). Useful for getting values "into" scripts together with the -- quiet
option.
-x, --extract-settings
Extract all mixer settings as a gom option line to stdout (e. g. for "setting=`gom --quiet
--extract-settings`" and "gom -- quiet $settings" later in a bash script).
-I, --read-stdin
Read options from stdin (until EOF).
ENVIRONMENT
HOME used as prefix for the configuration directory .gom/ for a non-root user.
FILES
/etc/gom/ system configuration directory (user root).
$HOME/.gom/ user configuration dir (all non-root users).
Files inside the configuration directory:
conf.default_mixer option file for default mixer (loaded on startup).
conf.gom option file (loaded on startup).
conf.initialize option file for initialization (loaded via --initialize).
<mixer-device>.default default options file for <mixer-device> (loaded with --get-options).
<mixer-device>.<name> mixer settings that can be easily accessed just by <name>
with --get-options=<name> when <mixer-device> is open."
DIAGNOSTICS
Exit status is 0 if no errors were detected while running gom; it is greater than 0 if one or more
errors were detected. This should be interpreted as warning, not necessarily as failure.
(The amount of detected errors will be printed out if the verbosity level is VERBOSE or higher; the
warning exit status is currently always 2, but this may change).
EXAMPLES
(This section is incomplete and most likely confusing ;).
1. gom as system startup
2. gom as user startup
3. gom in a running session
4. gom in scripts
5. Some more detailed examples
gom --interface=t, gom -it
Interactively manipulate mixer settings with the terminal gomii.
gom --get-settings, gom -G
(e.g. when you log in as user). Loads user's default options file.
gom --get-settings=cd, gom -Gcd
Loads options file "cd" (most likely a setting for playing cds).
gom -d/dev/mixer0 -M -d/dev/mixer1 -l100
First, mute mixer 0, then set the volume of the first channel on mixer 1 to 100.
gom -M -c vol -l 90 -c pcm -l 90 -e bplay super.voc -Z
Plays the sample super.voc on channel 4=pcm with all other channels muted, restoring original
mixer settings afterwards.
gom -ix -e <any_sound_player> -Z
Plays any sound, interactively setting the mixer before with the X gomii and restoring settings
afterwards.
AUTHOR
Copyright (c) 1996-2004 Stephan Alexander Sürken <absurd@olurdix.de> GPL. The X gomii of the gom package is also Copyright (c) Hannu Savolainen 1993 (as it is originally based on "xvmixer" by Hannu Savolainen). The gom package is licensed under the GPL (GNU General Public License). The files "README" and "COPYING" in the original distribution contain the exact terms.
SEE ALSO
gomconfig(8) Information about OSS can currently (1999 August 18) be found at "http://www.opensound.com/".
KNOWN BUGS
Gom does not detect recursion in option files (e.g. by adding a "-Gcd" to an options file named "cd").
There must always be at least one recording source, so when writing option files for gom "by hand", first
put all to-be-active recording sources on, then all to-be-inactive recording sources off, else one
recording source might not become inactive in unfortunate circumstances. Mixer settings automatically
written by gom are saved in this manner.
The mixer settings files may be inconsistent between different sound drivers (i.e., if the channel
numbering is different).
Loading settings from a options file that was saved from a different mixer may lead to errors (if some
option is not available on the current mixer), or to silently not-setting of newly available options of
the current mixer; saving mixer settings with the mixer name as prefix since 0.29.99 avoids this at least
for not explicitly given mixer settings file names.
The "text blocking output" cuts words (true, too, for the OPTIONS section of this manual page).
X gomii bugs:
The X gomii has some "bugs" due to xview and/or the lack of documentation available for the author (all
the rest of this section):
The X gomii creates its display objects with xview, but doesn't check for allocation errors. I guess
xview somehow handles this ;).
The X gomii's scroll window displays in a non-fixed font.
Some placements in the X gomii are still static; it could imagine that the display might look a little
bit screwed up if you use a different configuration than mine (e.g. a different font).
Xview, in general, "seems to be a little bit unstable" (the author itself locked all his major input
devices (i.e., mouse & keyboard (you should be so clever to have some other means to access your computer
when programming xview ;)) several times by using xview applications under X (not necessarily the X
gomii) for whatever unknown reasons (and without being able to reproduce the bug properly). (()())
KNOWINGLY NO BUGS
If starting gom results in loading and initializing the kernel sound driver (e.g. if the sound driver
gets kerneld-autoloaded under Linux), the sound card's settings are set to the driver's default by the
driver itself. gom has nothing to do with these defaults and doesn't change any settings -- any program
using the sound driver in that situation would have the same effect.