pulseaudio

pulseaudio(1)                General Commands Manual               pulseaudio(1)



NAME
       pulseaudio - The PulseAudio Sound System

SYNOPSIS
       pulseaudio [options]

       pulseaudio --help

       pulseaudio --version

       pulseaudio --dump-conf

       pulseaudio --dump-modules

       pulseaudio --dump-resample-methods

       pulseaudio --cleanup-shm

       pulseaudio --start

       pulseaudio --kill

       pulseaudio --check

DESCRIPTION
       PulseAudio is a networked low-latency sound server for Linux, POSIX and
       Windows systems.

OPTIONS
       -h | --help
              Show help.

       --version
              Show version information.

       --dump-conf
              Load the daemon configuration file daemon.conf (see below), parse
              remaining configuration options on the command line and dump the
              resulting daemon configuration, in a format that is compatible
              with daemon.conf.

       --dump-modules
              List available loadable modules. Combine with -v for a more
              elaborate listing.

       --dump-resample-methods
              List available audio resamplers.

       --cleanup-shm
              Identify stale PulseAudio POSIX shared memory segments in /dev/shm
              and remove them if possible. This is done implicitly whenever a
              new daemon starts up or a client tries to connect to a daemon. It
              should normally not be necessary to issue this command by hand.
              Only available on systems with POSIX shared memory segments
              implemented via a virtual file system mounted to /dev/shm (e.g.
              Linux).

       --start
              Start PulseAudio if it is not running yet. This is different from
              starting PulseAudio without --start which would fail if PA is
              already running. PulseAudio is guaranteed to be fully initialized
              when this call returns. Implies --daemonize.

       -k | --kill
              Kill an already running PulseAudio daemon of the calling user
              (Equivalent to sending a SIGTERM).

       --check
              Return 0 as return code when the PulseAudio daemon is already
              running for the calling user, or non-zero otherwise. Produces no
              output on the console except for errors to stderr.

              Note that a non-zero return value doesn't necessarily mean that
              PulseAudio is not usable. Even if the server is not running, it
              may get automatically started via PulseAudio's autospawning
              mechanism or systemd's socket activation, or the environment might
              be such that checking for processes doesn't work (for example, the
              running server might not show up in a container, even if the
              server is accessible via a socket). Also disabling PID files with
              --use-pid-file=no prevents --check from detecting running servers.

              A more robust check in most situations would be to try
              establishing a client connection to the server. Unfortunately
              there's currently no --check-connection option to replace --check,
              but running "pactl info" could be a pretty good substitute.

       --system[=BOOL]
              Run as system-wide instance instead of per-user. Please note that
              this disables certain features of PulseAudio and is generally not
              recommended unless the system knows no local users (e.g. is a thin
              client). This feature needs special configuration and a dedicated
              UNIX user set up. It is highly recommended to combine this with
              --disallow-module-loading (see below).

       -D | --daemonize[=BOOL]
              Daemonize after startup, i.e. detach from the terminal. Note that
              when running as a systemd service you should use --daemonize=no
              for systemd notification to work.

       --fail[=BOOL]
              Fail startup when any of the commands specified in the startup
              script default.pa (see below) fails.

       --high-priority[=BOOL]
              Try to acquire a high Unix nice level. This will only succeed if
              the calling user has a non-zero RLIMIT_NICE resource limit set (on
              systems that support this), or we're configured to be run as
              system daemon (see --system above). It is recommended to enable
              this, since it is only a negligible security risk (see below).

       --realtime[=BOOL]
              Try to acquire a real-time scheduling for PulseAudio's I/O
              threads. This will only succeed if the calling user has a non-zero
              RLIMIT_RTPRIO resource limit set (on systems that support this),
              or rtkit is available and allows PulseAudio to enable real-time
              scheduling, or we are configured to be run as system daemon (see
              --system above).

       --disallow-module-loading[=BOOL]
              Disallow module loading after startup. This is a security feature
              since it disallows additional module loading during runtime and on
              user request. It is highly recommended when --system is used (see
              above). Note however, that this breaks certain features like
              automatic module loading on hot plug.

       --disallow-exit[=BOOL]
              Disallow user requested exit

       --exit-idle-time=SECS
              Terminate the daemon after the last client quit and this time in
              seconds passed. Use a negative value to disable this feature.
              Defaults to 20.

              When PulseAudio runs in the per-user mode and detects a login
              session, then any positive value will be reset to 0 so that
              PulseAudio will terminate immediately on logout. A positive value
              therefore has effect only in environments where there's no support
              for login session tracking (or if the user is logged in without a
              session spawned, a.k.a. lingering). A negative value can still be
              used to disable any automatic exit.

              When PulseAudio runs in the system mode, automatic exit is always
              disabled, so this option does nothing.

       --scache-idle-time=SECS
              Unload autoloaded samples from the cache when they haven't been
              used for the specified number of seconds.

       --log-level[=LEVEL]
              If an argument is passed, set the log level to the specified
              value, otherwise increase the configured verbosity level by one.
              The log levels are numerical from 0 to 4, corresponding to error,
              warn, notice, info, debug. Default log level is notice, i.e. all
              log messages with lower log levels are printed: error, warn,
              notice.

       -v | --verbose
              Increase the configured verbosity level by one (see --log-level
              above). Specify multiple times to increase log level multiple
              times.

       --log-target={auto,syslog,journal,stderr,file:PATH,newfile:PATH}
              Specify the log target. If set to auto (which is the default),
              then logging is directed to syslog when --daemonize is passed,
              otherwise to STDERR. If set to journal logging is directed to the
              systemd journal. If set to file:PATH, logging is directed to the
              file indicated by PATH. newfile:PATH is otherwise the same as
              file:PATH, but existing files are never overwritten. If the
              specified file already exists, a suffix is added to the file name
              to avoid overwriting.

       --log-meta[=BOOL]
              Show source code location in log messages.

       --log-time[=BOOL]
              Show timestamps in log messages.

       --log-backtrace=FRAMES
              When FRAMES is greater than 0, log for each message a stack trace
              up to the number of specified stack frames.

       -p | --dl-search-path=PATH
              Set the search path for dynamic shared objects (plugins).

       --resample-method=METHOD
              Use the specified resampler by default (See --dump-resample-
              methods above for possible values).

       --use-pid-file[=BOOL]
              Create a PID file. If this options is disabled it is possible to
              run multiple sound servers per user.

       --no-cpu-limit[=BOOL]
              Do not install CPU load limiter on platforms that support it. By
              default, PulseAudio will terminate itself when it notices that it
              takes up too much CPU time. This is useful as a protection against
              system lockups when real-time scheduling is used (see below).
              Disabling this mechanism is useful when debugging PulseAudio with
              tools like valgrind(1) which slow down execution.

       --disable-shm[=BOOL]
              PulseAudio clients and the server can exchange audio data via
              POSIX or memfd shared memory segments (on systems that support
              this). If disabled PulseAudio will communicate exclusively over
              sockets. Please note that data transfer via shared memory segments
              is always disabled when PulseAudio is running with --system
              enabled (see above).

       --enable-memfd[=BOOL]
              PulseAudio clients and the server can exchange audio data via
              memfds - the anonymous Linux Kernel shared memory mechanism (on
              kernels that support this). If disabled PulseAudio will
              communicate via POSIX shared memory.

       -L | --load="MODULE ARGUMENTS"
              Load the specified plugin module with the specified arguments.

       -F | --file=FILENAME
              Run the specified script on startup. May be specified multiple
              times to specify multiple scripts to be run in order. Combine with
              -n to disable loading of the default script default.pa (see
              below).

       -C     Open a command interpreter on STDIN/STDOUT after startup. This may
              be used to configure PulseAudio dynamically during runtime.
              Equivalent to --load=module-cli.

       -n     Don't load default script file default.pa (see below) on startup.
              Useful in conjunction with -C or --file.

FILES
       ~/.config/pulse/daemon.conf, /etc/pulse/daemon.conf: configuration
       settings for the PulseAudio daemon. If the version in the user's home
       directory does not exist the global configuration file is loaded. See
       pulse-daemon.conf(5) for more information.

       ~/.config/pulse/default.pa, /etc/pulse/default.pa: the default
       configuration script to execute when the PulseAudio daemon is started. If
       the version in the user's home directory does not exist the global
       configuration script is loaded. See default.pa(5) for more information.

       ~/.config/pulse/client.conf, /etc/pulse/client.conf: configuration
       settings for PulseAudio client applications. If the version in the user's
       home directory does not exist the global configuration file is loaded.
       See pulse-client.conf(5) for more information.

SIGNALS
       SIGINT, SIGTERM: the PulseAudio daemon will shut down (Same as --kill).

       SIGHUP: dump a long status report to STDOUT or syslog, depending on the
       configuration.

       SIGUSR1: load module-cli, allowing runtime reconfiguration via
       STDIN/STDOUT.

       SIGUSR2: load module-cli-protocol-unix, allowing runtime reconfiguration
       via a AF_UNIX socket. See pacmd(1) for more information.

UNIX GROUPS AND USERS
       Group pulse-access: if PulseAudio is running as a system daemon (see
       --system above) access is granted to members of this group when they
       connect via AF_UNIX sockets. If PulseAudio is running as a user daemon
       this group has no meaning.

       User pulse, group pulse: if PulseAudio is running as a system daemon (see
       --system above) and is started as root the daemon will drop privileges
       and become a normal user process using this user and group. If PulseAudio
       is running as a user daemon this user and group has no meaning.

REAL-TIME AND HIGH-PRIORITY SCHEDULING
       To minimize the risk of drop-outs during playback it is recommended to
       run PulseAudio with real-time scheduling if the underlying platform
       supports it. This decouples the scheduling latency of the PulseAudio
       daemon from the system load and is thus the best way to make sure that
       PulseAudio always gets CPU time when it needs it to refill the hardware
       playback buffers. Unfortunately this can be a security risk on some
       systems, since PulseAudio runs as user process, and giving realtime
       scheduling privileges to a user always comes with the risk that the user
       misuses it to lock up the system -- which is possible since making a
       process real-time effectively disables preemption. To solve this problem,
       PulseAudio uses rtkit to safely acquire real-time scheduling when
       available.

       If the risk of locking up the machine is considered too big to enable
       real-time scheduling, high-priority scheduling can be enabled instead
       (i.e. negative nice level). This can be enabled by passing --high-
       priority (see above) when starting PulseAudio and may also be enabled
       with the appropriate option in daemon.conf. Negative nice levels can only
       be enabled when the appropriate resource limit RLIMIT_NICE is set (see
       setrlimit(2) for more information), possibly configured in
       /etc/security/limits.conf. A resource limit of 31 (corresponding with
       nice level -11) is recommended.

ENVIRONMENT VARIABLES
       The PulseAudio client libraries check for the existence of the following
       environment variables and change their local configuration accordingly:

       $PULSE_SERVER: the server string specifying the server to connect to when
       a client asks for a sound server connection and doesn't explicitly ask
       for a specific server. The server string is a list of server addresses
       separated by whitespace which are tried in turn. A server address
       consists of an optional address type specifier (unix:, tcp:, tcp4:,
       tcp6:), followed by a path or host address. A host address may include an
       optional port number. A server address may be prefixed by a string
       enclosed in {}. In this case the following server address is ignored
       unless the prefix string equals the local hostname or the machine id
       (/etc/machine-id).

       $PULSE_SINK: the symbolic name of the sink to connect to when a client
       creates a playback stream and doesn't explicitly ask for a specific sink.

       $PULSE_SOURCE: the symbolic name of the source to connect to when a
       client creates a record stream and doesn't explicitly ask for a specific
       source.

       $PULSE_BINARY: path of PulseAudio executable to run when server auto-
       spawning is used.

       $PULSE_CLIENTCONFIG: path of file that shall be read instead of
       client.conf (see above) for client configuration.

       $PULSE_COOKIE: path of file that contains the PulseAudio authentication
       cookie. Defaults to ~/.config/pulse/cookie.

       These environment settings take precedence -- if set -- over the
       configuration settings from client.conf (see above).

AUTHORS
       The PulseAudio Developers <pulseaudio-discuss (at) lists (dot)
       freedesktop (dot) org>; PulseAudio is available from
       http://pulseaudio.org/

SEE ALSO
       pulse-daemon.conf(5), default.pa(5), pulse-client.conf(5), pacmd(1)



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