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SNDIOCTL(1) FreeBSD General Commands Manual SNDIOCTL(1) NAME sndioctl - manipulate audio device controls SYNOPSIS sndioctl [-dimnqv] [-f device] [command ...] DESCRIPTION The sndioctl utility can display or manipulate controls of sndio(7) audio devices, like the output level. The options are as follows: -d Dump the raw list of available controls and exit. Useful as a debugging tool. -f device Use this sndio(7) audio device. -i Display characteristics of requested controls instead of their values. -m Monitor and display audio controls changes. -n Suppress printing of the variable name. -q Suppress all printing when setting a variable. -v Enable verbose mode, a.k.a. multi-channel mode. By default controls affecting different channels of the same stream are disguised as a single mono control to hide details that are not essential. If no commands are specified, all valid controls are displayed on standard output. Unless -d, -m, -n, or -i are used, displayed lines are valid commands. The set of available controls depends on the audio device. Commands use the following two formats to display and change controls respectively: [group/]stream[channel].function [group/]stream[channel].function=value On the left-hand side are specified the control group (if any), the affected stream name, and the optional channel number. Examples of left- hand side terms: output.level output[0].level If the channel number (including the brackets) is omitted, the command is applied to all channels. Values are numbers between 0 and 1. Two-state controls (switches) take either 0 or 1 as value, typically corresponding to the off and on states respectively. If a decimal is prefixed by the plus (minus) sign then the given value is added to (subtracted from) the current value of the control. If "!" is used instead of a number, then the switch is toggled. EXAMPLES Increase the level control affecting all output channels by 10% of the maximum: $ sndioctl output.level=+0.1 Mute all output channels: $ sndioctl output.mute=1 Toggle the above mute control: $ sndioctl output.mute=! Allow audio recording and set all input channels to 50%: # sysctl kern.audio.record=1 $ sndioctl input.mute=0 input.level=0.5 SEE ALSO sioctl_open(3) FreeBSD 14.1-RELEASE-p8 February 9, 2025 FreeBSD 14.1-RELEASE-p8