Ubuntu Manpage: beep - beep the pc speaker any number of ways

Provided by: beep_1.4.9-1.1ubuntu2_amd64

NAME

       beep - beep the pc speaker any number of ways

SYNOPSIS

       beep [GLOBALS] [-f FREQ] [-l LEN] [-r REPEATS] [<-d|-D> DELAY] [-s] [-c]
       beep [GLOBALS] <TONE_OPTIONS> [-n|--new] <TONE_OPTIONS>
       beep <-h|--help>
       beep <-v|-V|--version>

DESCRIPTION

       beep  allows  the user to control the PC speaker with precision, allowing different sounds
       to indicate different events.  While beep can be run quite happily on  the  command  line,
       beep's  intended  use  is  within  shell/perl  scripts,  notifying the user when something
       interesting occurs.  Of course, it has no notion of what IS interesting, but it is good at
       the notifying part.

       All  options have default values, meaning that just typing 'beep' will work.  If an option
       is specified more than once  on  the  command  line,  subsequent  options  override  their
       predecessors.  So 'beep -f 200 -f 300' will beep at 300Hz.

       All durations are given in a unit of milliseconds, frequencies as Hertz, and the number of
       repeats is a dimensionless number.

OPTIONS

Global options
-e DEVICE, --device=DEVICE
Explicitly set the device beep shall use to generate beep tones. When not given a
device explicitly, beep runs through an internal list of devices until one appears
to work.

--debug, --verbose
Make the beep program more verbose.

Tone options
-f FREQ
Beep with a tone frequency of FREQ Hz, where 0 < FREQ < 20000. As a general
ballpark, the regular terminal beep is around 750Hz. For backwards compatibility,
you can give FREQ as a floating point number, but beep will round that to integer
values as the kernel APIs expect them. Default value: 440 Hz.

-l LEN Beep for a tone length of LEN milliseconds. Default value: 200 ms.

-r REPEATS
Repeat the tone including delays REPEATS times. Default value: 1 tone, not
repeated.

-d DELAY | -D DELAY
Specify a delay of DELAY milliseconds between repetitions. Small letter -d
specifies that this delay should only occur between beeps, that is, it should not
occur after the last repetition. Capital letter -D specifies that the delay should
occur after every repetition, including after the last one. Normally, -d is what
you want, but if, for example, you are stringing several beep commands together to
play the star wars anthem, you may want control over every delay. Default value:
100 ms delay between beeps with no delay after the last beep.

-n, --new
The --new option allows you to chain multiple beeps together on a single command
line. Each time the --new is used, beep starts treating all further arguments as
though they were for a new beep. So for example:

beep -f 1000 -n -f 2000 -n -f 1500

would produce a sequence of three beeps, the first with a frequency of 1000Hz (and
otherwise default values), then a second beep with a frequency of 2000Hz (again,
with things like delay and reps being set to their defaults), then a third beep, at
1500Hz. This is different from specifying a -r value, since -r repeats the same
beep multiple times, whereas --new allows you to specify different beeps. After a
--new, the new beep is created with all the default values, and any of these can be
specified without altering values for preceding (or later) beeps. See the EXAMPLES
section if this managed to confuse you.

-s, -c Both the -s and the -c option put beep into input processing mode, reading from
stdin and copying all received data to stdout. This makes it easy to slip beep
into a text processing pipeline to acoustically monitor the data flow within that
pipeline. See the EXAMPLES section.

-c Beep after every character received.

-s Beep after every set of data received. Usually, this means after newlines
occur in text processing pipes.

In a sequence of notes specified with one or more occurrences of -n or --new, it
only makes sense to have one single note marked with either -s or -c attached to
it. Then beep will beep all notes until it reaches that marked note, then repeat
the marked note according to the input it receives, and once the input has reached
EOF, beep will continue with the remainder of the note sequence.

The behaviour of beep with more than one note marked with -s or -c is undefined.

Other Actions
-h, --help Display beep usage info and exit.

-v, -V, --version
Display beep version information and exit.

EXIT STATUS

       When successful, beep returns with exit code 0.

       Any non-0 exit code means beep has encountered an error and has bailed out.

ENVIRONMENT

       BEEP_LOG_LEVEL
              When  set  to  a  number  between  -999 and 999, BEEP_LOG_LEVEL will be used as the
              default loglevel until overridden by a command line parameter.

FILES

       The device files beep uses by default are the following:
           /dev/input/by-path/platform-pcspkr-event-spkr
           /dev/tty0
           /dev/vc/0

NOTES

Devices and Permissions
When you run beep without explicitly giving a device to use, beep tries opening the
following devices in sequence until one succeeds:

/dev/input/by-path/platform-pcspkr-event-spkr
Uses the evdev API, and system administrator can allow access to any set of users and
groups using the normal file permissions.

/dev/tty0
Uses the console API, and the kernel insists you are root or own the TTY.

/dev/vc/0
Uses the console API, and the kernel insists you are root or own the TTY.

beep does not support running as setuid root or via sudo(1).

For non-root uses, the system administrator can set up a udev(7) rule to allow write
access to /dev/input/by-path/platform-pcspkr-event-spkr for certain users and/or user
groups. For details, see the beep /usr/share/doc/beep/PERMISSIONS.md file.

APIs
evdev
Uses the input event device driver, which means running write(2) on
/dev/input/by-path/platform-pcspkr-event-spkr.

The permissions to this device file can be set up such that beep can be run by any
non-root user the system administrator wants to.

Opening this device takes on the order of magnitude of 20ms in the Linux kernel for
every time you start the beep command. Therefore, if you need to play multiple notes
in a rhythmical sequence for a melody, use one beep command invocation with multiple
notes, not several beep invocations playing one note each.

console
Uses the ancient console API, which means running the KIOCSOUND ioctl(2) on a tty
device like /dev/tty0 or /dev/vc/0.

This requires being root, unless the non-root user happens be logged into the virtual
console and be using that specific virtual console device like e.g. /dev/tty4. This
makes the console driver useless for non-root users logged in via ssh, and often X11
or Wayland.

Use the evdev API instead.

Concurrent Invocations
Concurrent invocations of beep are not supported. There is only one tone generator in the
PC hardware, and we do not manage access to that shared resource in any way. So if a
first beep -f 1000 -l 10000 process starts a long 10 second beep with 1000Hz, and 2
seconds later a second quick beep -f 2050 -l 100 with 2050Hz comes in, you will hear that
2050Hz beep for 100ms, and then silence as the quick beep silences the tone generator. Now
you will not hear that the first beep process is still running after having waited for the
first 2100ms of its 10000ms. You will also not hear that the first beep process will
silence the already silent speaker 7900ms later, i.e. 10000ms after the first beep
started.

Sound Volume
The PC speaker hardware has no way to explicitly set the volume of a beep.

If you have a standalone PC, however, chances are you have a piezo beeper connected to the
mainboard. If you prioritize a loud beep over a certain frequency beep, you can choose to
beep at a frequency close to the resonance frequency of the piezo beeper. Typical piezo
beepers have a resonance frequency around 2000Hz, so you can test frequencies around that
range. The author's piezo beeper is the loudest at about 2050Hz.

If you have a PC laptop, chances are that your laptop will not have a piezo beeper
hardware inside and that it will route the output of the pcspkr circuit to the laptop's
internal speakers via the sound card mixer. In that case, you can and/or must change the
mixer level for the beeper using a sound card mixer application.

Frequency Table
This frequency table might come in handy for translating musical notes to frequencies.
The frequencies are rounded to integer numbers as the kernel driver only works with
integers. The column for octave 4 is the octave of middle C.

┌─────┬─────────────────────────┐
│note │ octave │
│name │ 3 4 5 6 │
├─────├─────────────────────────┤
│ C │ 131 262 523 1047 │
│ C# │ 139 277 554 1109 │
│ D │ 147 294 587 1175 │
│ D# │ 156 311 622 1245 │
│ E │ 165 330 659 1319 │
│ F │ 175 349 698 1397 │
│ F# │ 185 370 740 1480 │
│ G │ 196 392 784 1568 │
│ G# │ 208 415 831 1661 │
│ A │ 220 440 880 1760 │
│ A# │ 233 466 932 1865 │
│ B │ 247 494 988 1976 │
│ C │ 262 523 1047 2093 │
└─────┴─────────────────────────┘

BUGS

       Report bugs to ⟨https://github.com/spkr-beep/beep/issues⟩.

EXAMPLES

       At its simplest (yet still effective)

           beep

       A more interesting standalone setup

           beep -f 300.7 -r 2 -d 100 -l 400

       As part of a log watching pipeline

           tail -f /var/log/xferlog | grep 'passwd' | beep -f 1000 -r 5 -s

       When using -c mode, I recommend using a short -D, and a shorter -l, so that the  beeps  do
       not   blur   together.    Something   like  this  will  get  you  a  cheesy  1970's  style
       beep-as-you-type-each-letter effect

           cat file | beep -c -f 400 -D 50 -l 10

       A highly contrived example of -n/--new usage

           beep -f 1000 -r 2 -n -r 5 -l 10 --new

       will produce first two 1000Hz beeps, then 5 beeps at the default tone, but only 10ms  long
       each, followed by a third beep using all the default settings (since none are specified).