xref: /third_party/pulseaudio/man/pulseaudio.1.xml.in (revision 53a5a1b3)

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<manpage name="pulseaudio" section="1" desc="The PulseAudio Sound System">

  <synopsis>
    <cmd>pulseaudio [<arg>options</arg>]</cmd>
    <cmd>pulseaudio <opt>--help</opt></cmd>
    <cmd>pulseaudio <opt>--version</opt></cmd>
    <cmd>pulseaudio <opt>--dump-conf</opt></cmd>
    <cmd>pulseaudio <opt>--dump-modules</opt></cmd>
    <cmd>pulseaudio <opt>--dump-resample-methods</opt></cmd>
    <cmd>pulseaudio <opt>--cleanup-shm</opt></cmd>
    <cmd>pulseaudio <opt>--start</opt></cmd>
    <cmd>pulseaudio <opt>--kill</opt></cmd>
    <cmd>pulseaudio <opt>--check</opt></cmd>
  </synopsis>

  <description>
    <p>PulseAudio is a networked low-latency sound server for Linux, POSIX and Windows systems.</p>
  </description>

  <options>

    <option>
      <p><opt>-h | --help</opt></p>

      <optdesc><p>Show help.</p></optdesc>
    </option>

    <option>
      <p><opt>--version</opt></p>

      <optdesc><p>Show version information.</p></optdesc>
    </option>

    <option>
      <p><opt>--dump-conf</opt></p>

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

    <option>
      <p><opt>--dump-modules</opt></p>

      <optdesc><p>List available loadable modules. Combine with
      <opt>-v</opt> for a more elaborate listing.</p></optdesc>
    </option>

    <option>
      <p><opt>--dump-resample-methods</opt></p>
      <optdesc><p>List available audio resamplers.</p></optdesc>
    </option>

    <option>
      <p><opt>--cleanup-shm</opt></p>

      <optdesc><p>Identify stale PulseAudio POSIX shared memory
      segments in <file>/dev/shm</file> 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 <file>/dev/shm</file>
      (e.g. Linux).</p></optdesc>
    </option>

    <option>
      <p><opt>--start</opt></p>

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

    <option>
      <p><opt>-k | --kill</opt></p>

      <optdesc><p>Kill an already running PulseAudio daemon of the
      calling user (Equivalent to sending a SIGTERM).</p></optdesc>
    </option>

    <option>
      <p><opt>--check</opt></p>

      <optdesc><p>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.</p>

      <p>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
      <opt>--use-pid-file=no</opt> prevents <opt>--check</opt> from
      detecting running servers.</p>

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


    <option>
      <p><opt>--system</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>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
      <opt>--disallow-module-loading</opt> (see below).</p></optdesc>
    </option>

    <option>
      <p><opt>-D | --daemonize</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>Daemonize after startup, i.e. detach from the
      terminal. Note that when running as a systemd service you should
      use <opt>--daemonize=no</opt> for systemd notification to work.
      </p></optdesc>
    </option>

    <option>
      <p><opt>--fail</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>Fail startup when any of the commands specified in
      the startup script <file>default.pa</file> (see below)
      fails.</p></optdesc>
    </option>

    <option>
      <p><opt>--high-priority</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>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 <arg>--system</arg> above). It is recommended
      to enable this, since it is only a negligible security risk (see
      below).</p></optdesc>
    </option>

    <option>
      <p><opt>--realtime</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>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 <arg>--system</arg> above).</p></optdesc>
    </option>

    <option>
      <p><opt>--disallow-module-loading</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>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 <arg>--system</arg> is used (see above). Note however, that
      this breaks certain features like automatic module loading on hot
      plug.</p></optdesc>

    </option>

    <option>
      <p><opt>--disallow-exit</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>Disallow user requested exit</p></optdesc>
    </option>

    <option>
      <p><opt>--exit-idle-time</opt><arg>=SECS</arg></p>

      <optdesc>
        <p>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.</p>

        <p>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.</p>

        <p>When PulseAudio runs in the system mode, automatic exit is always
        disabled, so this option does nothing.</p>
      </optdesc>
    </option>

    <option>
      <p><opt>--scache-idle-time</opt><arg>=SECS</arg></p>

      <optdesc><p>Unload autoloaded samples from the cache when they
      haven't been used for the specified number of
      seconds.</p></optdesc>
    </option>

    <option>
      <p><opt>--log-level</opt><arg>[=LEVEL]</arg></p>

      <optdesc><p>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 <arg>error</arg>, <arg>warn</arg>,
      <arg>notice</arg>, <arg>info</arg>, <arg>debug</arg>. Default
      log level is <arg>notice</arg>, i.e. all log messages with lower
      log levels are printed: <arg>error</arg>, <arg>warn</arg>,
      <arg>notice</arg>.</p></optdesc>
    </option>

    <option>
      <p><opt>-v | --verbose</opt></p>

      <optdesc><p>Increase the configured verbosity level by one (see
      <opt>--log-level</opt> above). Specify multiple times to
      increase log level multiple times.</p></optdesc>
    </option>

    <option>
      <p><opt>--log-target</opt><arg>={auto,syslog,journal,stderr,file:PATH,newfile:PATH}</arg></p>

      <optdesc><p>Specify the log target. If set to <arg>auto</arg>
      (which is the default), then logging is directed to syslog when
      <opt>--daemonize</opt> is passed, otherwise to
      STDERR. If set to <arg>journal</arg> logging is directed to the systemd
      journal. If set to <arg>file:PATH</arg>, logging is directed to
      the file indicated by PATH. <arg>newfile:PATH</arg> 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.</p></optdesc>
    </option>

    <option>
      <p><opt>--log-meta</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>Show source code location in log messages.</p></optdesc>
    </option>

    <option>
      <p><opt>--log-time</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>Show timestamps in log messages.</p></optdesc>
    </option>

    <option>
      <p><opt>--log-backtrace</opt><arg>=FRAMES</arg></p>

      <optdesc><p>When FRAMES is greater than 0, log for each message a
      stack trace up to the number of specified stack frames.</p></optdesc>
    </option>

    <option>
      <p><opt>-p | --dl-search-path</opt><arg>=PATH</arg></p>

      <optdesc><p>Set the search path for dynamic shared objects
      (plugins).</p></optdesc>
    </option>

    <option>
      <p><opt>--resample-method</opt><arg>=METHOD</arg></p>

      <optdesc><p>Use the specified resampler by default (See
      <opt>--dump-resample-methods</opt> above for possible
      values).</p></optdesc>
    </option>

    <option>
      <p><opt>--use-pid-file</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>Create a PID file. If this options is disabled it is possible to run multiple sound servers per user.</p></optdesc>
    </option>

    <option>
      <p><opt>--no-cpu-limit</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>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 <manref name="valgrind"
      section="1"/> which slow down execution.</p></optdesc>
    </option>

    <option>
      <p><opt>--disable-shm</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>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
      <opt>--system</opt> enabled (see above).</p></optdesc>
    </option>

    <option>
      <p><opt>--enable-memfd</opt><arg>[=BOOL]</arg></p>

      <optdesc><p>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.</p></optdesc>
    </option>

    <option>
      <p><opt>-L | --load</opt><arg>="MODULE ARGUMENTS"</arg></p>

      <optdesc><p>Load the specified plugin module with the specified
      arguments.</p></optdesc>
    </option>

    <option>
      <p><opt>-F | --file</opt><arg>=FILENAME</arg></p>

      <optdesc><p>Run the specified script on startup. May be
      specified multiple times to specify multiple scripts to be run
      in order. Combine with <opt>-n</opt> to disable loading of the
      default script <file>default.pa</file> (see below).</p></optdesc>
    </option>
    <option>
      <p><opt>-C</opt></p>

      <optdesc><p>Open a command interpreter on STDIN/STDOUT after
      startup. This may be used to configure PulseAudio dynamically
      during runtime. Equivalent to
      <opt>--load</opt><arg>=module-cli</arg>.</p></optdesc>
    </option>
    <option>
      <p><opt>-n</opt></p>

      <optdesc><p>Don't load default script file
      <file>default.pa</file> (see below) on startup. Useful in
      conjunction with <opt>-C</opt> or
      <opt>--file</opt>.</p></optdesc>
    </option>


  </options>

  <section name="Files">

    <p><file>~/.config/pulse/daemon.conf</file>,
    <file>@PA_DEFAULT_CONFIG_DIR@/daemon.conf</file>: 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 <manref name="pulse-daemon.conf" section="5"/> for
    more information.</p>

    <p><file>~/.config/pulse/default.pa</file>,
    <file>@PA_DEFAULT_CONFIG_DIR@/default.pa</file>: 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 <manref name="default.pa"
    section="5"/> for more information.</p>

    <p><file>~/.config/pulse/client.conf</file>,
    <file>@PA_DEFAULT_CONFIG_DIR@/client.conf</file>: 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 <manref name="pulse-client.conf" section="5"/> for
    more information.</p>

  </section>

  <section name="Signals">

    <p><arg>SIGINT, SIGTERM</arg>: the PulseAudio daemon will shut
    down (Same as <opt>--kill</opt>).</p>

    <p><arg>SIGHUP</arg>: dump a long status report to STDOUT or
    syslog, depending on the configuration.</p>

    <p><arg>SIGUSR1</arg>: load module-cli, allowing runtime
    reconfiguration via STDIN/STDOUT.</p>

    <p><arg>SIGUSR2</arg>: load module-cli-protocol-unix, allowing
    runtime reconfiguration via a AF_UNIX socket. See <manref
    name="pacmd" section="1"/> for more information.</p>

  </section>

  <section name="UNIX Groups and users">

    <p>Group <arg>pulse-access</arg>: if PulseAudio is running as a system
    daemon (see <opt>--system</opt> 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.</p>

    <p>User <arg>pulse</arg>, group <arg>pulse</arg>: if PulseAudio is running as a system
    daemon (see <opt>--system</opt> 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.</p>
  </section>

  <section name="Real-time and high-priority scheduling">
    <p>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.</p>

    <p>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 <opt>--high-priority</opt> (see above)
    when starting PulseAudio and may also be enabled with the
    appropriate option in <file>daemon.conf</file>. Negative nice
    levels can only be enabled when the appropriate resource limit
    RLIMIT_NICE is set (see <manref name="setrlimit" section="2"/> for
    more information), possibly configured in
    <file>/etc/security/limits.conf</file>. A resource limit of 31
    (corresponding with nice level -11) is recommended.</p>
  </section>

  <section name="Environment variables">

    <p>The PulseAudio client libraries check for the existence of the
    following environment variables and change their local configuration accordingly:</p>

    <p><arg>$PULSE_SERVER</arg>: 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).</p>

    <p><arg>$PULSE_SINK</arg>: 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.</p>

    <p><arg>$PULSE_SOURCE</arg>: 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.</p>

    <p><arg>$PULSE_BINARY</arg>: path of PulseAudio executable to run when server auto-spawning is used.</p>

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

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

    <p>These environment settings take precedence -- if set -- over the configuration settings from <file>client.conf</file> (see above).</p>

  </section>

  <section name="Authors">
    <p>The PulseAudio Developers &lt;@PACKAGE_BUGREPORT@&gt;; PulseAudio is available from <url href="@PACKAGE_URL@"/></p>
  </section>

  <section name="See also">
    <p>
      <manref name="pulse-daemon.conf" section="5"/>, <manref name="default.pa" section="5"/>, <manref name="pulse-client.conf" section="5"/>, <manref name="pacmd" section="1"/>
    </p>
  </section>

</manpage>