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  23
  24 <manpage name="pulseaudio" section="1" desc="The PulseAudio Sound System">
  25
  26   <synopsis>
  27     <cmd>pulseaudio [<arg>options</arg>]</cmd>
  28     <cmd>pulseaudio <opt>--help</opt></cmd>
  29     <cmd>pulseaudio <opt>--version</opt></cmd>
  30     <cmd>pulseaudio <opt>--dump-conf</opt></cmd>
  31     <cmd>pulseaudio <opt>--dump-modules</opt></cmd>
  32     <cmd>pulseaudio <opt>--dump-resample-methods</opt></cmd>
  33     <cmd>pulseaudio <opt>--cleanup-shm</opt></cmd>
  34     <cmd>pulseaudio <opt>--start</opt></cmd>
  35     <cmd>pulseaudio <opt>--kill</opt></cmd>
  36     <cmd>pulseaudio <opt>--check</opt></cmd>
  37   </synopsis>
  38
  39   <description>
  40     <p>PulseAudio is a networked low-latency sound server for Linux, POSIX and Windows systems.</p>
  41   </description>
  42
  43   <options>
  44
  45     <option>
  46       <p><opt>-h | --help</opt></p>
  47
  48       <optdesc><p>Show help.</p></optdesc>
  49     </option>
  50
  51     <option>
  52       <p><opt>--version</opt></p>
  53
  54       <optdesc><p>Show version information.</p></optdesc>
  55     </option>
  56
  57     <option>
  58       <p><opt>--dump-conf</opt></p>
  59
  60       <optdesc><p>Load the daemon configuration file
  61       <file>daemon.conf</file> (see below), parse remaining
  62       configuration options on the command line and dump the resulting
  63       daemon configuration, in a format that is compatible with
  64       <file>daemon.conf</file>.</p></optdesc>
  65     </option>
  66
  67     <option>
  68       <p><opt>--dump-modules</opt></p>
  69
  70       <optdesc><p>List available loadable modules. Combine with
  71       <opt>-v</opt> for a more elaborate listing.</p></optdesc>
  72     </option>
  73
  74     <option>
  75       <p><opt>--dump-resample-methods</opt></p>
  76       <optdesc><p>List available audio resamplers.</p></optdesc>
  77     </option>
  78
  79     <option>
  80       <p><opt>--cleanup-shm</opt></p>
  81
  82       <optdesc><p>Identify stale PulseAudio POSIX shared memory
  83       segments in <file>/dev/shm</file> and remove them if
  84       possible. This is done implicitly whenever a new daemon starts
  85       up or a client tries to connect to a daemon. It should normally
  86       not be necessary to issue this command by hand. Only available
  87       on systems with POSIX shared memory segments implemented via a
  88       virtual file system mounted to <file>/dev/shm</file>
  89       (e.g. Linux).</p></optdesc>
  90     </option>
  91
  92     <option>
  93       <p><opt>--start</opt></p>
  94
  95       <optdesc><p>Start PulseAudio if it is not running yet. This is
  96       different from starting PulseAudio without <opt>--start</opt>
  97       which would fail if PA is already running. PulseAudio is
  98       guaranteed to be fully initialized when this call
  99       returns. Implies <opt>--daemon</opt>.</p></optdesc>
 100     </option>
 101
 102     <option>
 103       <p><opt>-k | --kill</opt></p>
 104
 105       <optdesc><p>Kill an already running PulseAudio daemon of the
 106       calling user (Equivalent to sending a SIGTERM).</p></optdesc>
 107     </option>
 108
 109     <option>
 110       <p><opt>--check</opt></p>
 111
 112       <optdesc><p>Return 0 as return code when the PulseAudio daemon
 113       is already running for the calling user, or non-zero
 114       otherwise. Produces no output on the console except for errors
 115       to stderr.</p></optdesc>
 116     </option>
 117
 118
 119     <option>
 120       <p><opt>--system</opt><arg>[=BOOL]</arg></p>
 121
 122       <optdesc><p>Run as system-wide instance instead of
 123       per-user. Please note that this disables certain features of
 124       PulseAudio and is generally not recommended unless the system
 125       knows no local users (e.g. is a thin client). This feature needs
 126       special configuration and a dedicated UNIX user set up. It is
 127       highly recommended to combine this with
 128       <opt>--disallow-module-loading</opt> (see below).</p></optdesc>
 129     </option>
 130
 131     <option>
 132       <p><opt>-D | --daemonize</opt><arg>[=BOOL]</arg></p>
 133
 134       <optdesc><p>Daemonize after startup, i.e. detach from the
 135       terminal.</p></optdesc>
 136     </option>
 137
 138     <option>
 139       <p><opt>--fail</opt><arg>[=BOOL]</arg></p>
 140
 141       <optdesc><p>Fail startup when any of the commands specified in
 142       the startup script <file>default.pa</file> (see below)
 143       fails.</p></optdesc>
 144     </option>
 145
 146     <option>
 147       <p><opt>--high-priority</opt><arg>[=BOOL]</arg></p>
 148
 149       <optdesc><p>Try to acquire a high Unix nice level. This will
 150       only succeed if the calling user has a non-zero RLIMIT_NICE
 151       resource limit set (on systems that support this), or we're
 152       called SUID root (see below), or we are configure to be run as
 153       system daemon (see <arg>--system</arg> above). It is recommended
 154       to enable this, since it is only a negligible security risk (see
 155       below).</p></optdesc>
 156     </option>
 157
 158     <option>
 159       <p><opt>--realtime</opt><arg>[=BOOL]</arg></p>
 160
 161       <optdesc><p>Try to acquire a real-time scheduling for
 162       PulseAudio's I/O threads. This will only succeed if the calling
 163       user has a non-zero RLIMIT_RTPRIO resource limit set (on systems
 164       that support this), or we're called SUID root (see below), or we
 165       are configure to be run as system daemon (see
 166       <arg>--system</arg> above). It is recommended to enable this
 167       only for trusted users, since it is a major security risk (see
 168       below).</p></optdesc>
 169     </option>
 170
 171     <option>
 172       <p><opt>--disallow-module-loading</opt><arg>[=BOOL]</arg></p>
 173
 174       <optdesc><p>Disallow module loading after startup. This is a
 175       security feature since it disallows additional module loading
 176       during runtime and on user request. It is highly recommended
 177       when <arg>--system</arg> is used (see above). Note however, that
 178       this breaks certain features like automatic module loading on hot
 179       plug.</p></optdesc>
 180
 181     </option>
 182
 183     <option>
 184       <p><opt>--exit-idle-time</opt><arg>=SECS</arg></p>
 185
 186       <optdesc><p>Terminate the daemon when idle and the specified
 187       number of seconds passed.</p></optdesc>
 188     </option>
 189
 190     <option>
 191       <p><opt>--scache-idle-time</opt><arg>=SECS</arg></p>
 192
 193       <optdesc><p>Unload autoloaded samples from the cache when the
 194       haven't been used for the specified number of
 195       seconds.</p></optdesc>
 196     </option>
 197
 198     <option>
 199       <p><opt>--log-level</opt><arg>[=LEVEL]</arg></p>
 200
 201       <optdesc><p>If an argument is passed, set the log level to the
 202       specified value, otherwise increase the configured verbosity
 203       level by one. The log levels are numerical from 0 to 4,
 204       corresponding to <arg>error</arg>, <arg>warn</arg>,
 205       <arg>notice</arg>, <arg>info</arg>, <arg>debug</arg>. Default
 206       log level is <arg>notice</arg>, i.e. all log messages with lower
 207       log levels are printed: <arg>error</arg>, <arg>warn</arg>,
 208       <arg>notice</arg>.</p></optdesc>
 209     </option>
 210
 211     <option>
 212       <p><opt>-v</opt></p>
 213
 214       <optdesc><p>Increase the configured verbosity level by one (see
 215       <opt>--log-level</opt> above). Specify multiple times to
 216       increase log level multiple times.</p></optdesc>
 217     </option>
 218
 219     <option>
 220       <p><opt>--log-target</opt><arg>={auto,syslog,journal,stderr,file:PATH,newfile:PATH}</arg></p>
 221
 222       <optdesc><p>Specify the log target. If set to <arg>auto</arg>
 223       (which is the default), then logging is directed to syslog when
 224       <opt>--daemonize</opt> is passed, otherwise to
 225       STDERR. If set to <arg>journal</arg> logging is directed to the systemd
 226       journal. If set to <arg>file:PATH</arg>, logging is directed to
 227       the file indicated by PATH. <arg>newfile:PATH</arg> is otherwise
 228       the same as file:PATH, but existing files are never overwritten.
 229       If the specified file already exists, a suffix is added to the
 230       file name to avoid overwriting.</p></optdesc>
 231     </option>
 232
 233     <option>
 234       <p><opt>--log-meta</opt><arg>[=BOOL]</arg></p>
 235
 236       <optdesc><p>Show source code location in log messages.</p></optdesc>
 237     </option>
 238
 239     <option>
 240       <p><opt>--log-time</opt><arg>[=BOOL]</arg></p>
 241
 242       <optdesc><p>Show timestamps in log messages.</p></optdesc>
 243     </option>
 244
 245     <option>
 246       <p><opt>--log-backtrace</opt><arg>=FRAMES</arg></p>
 247
 248       <optdesc><p>When FRAMES is greater than 0, log for each message a
 249       stack trace up to the number of specified stack frames.</p></optdesc>
 250     </option>
 251
 252     <option>
 253       <p><opt>--p | --dl-search-path</opt><arg>=PATH</arg></p>
 254
 255       <optdesc><p>Set the search path for dynamic shared objects
 256       (plugins).</p></optdesc>
 257     </option>
 258
 259     <option>
 260       <p><opt>--resample-method</opt><arg>=METHOD</arg></p>
 261
 262       <optdesc><p>Use the specified resampler by default (See
 263       <opt>--dump-resample-methods</opt> above for possible
 264       values).</p></optdesc>
 265     </option>
 266
 267     <option>
 268       <p><opt>--use-pid-file</opt><arg>[=BOOL]</arg></p>
 269
 270       <optdesc><p>Create a PID file. If this options is disabled it is possible to run multiple sound servers per user.</p></optdesc>
 271     </option>
 272
 273     <option>
 274       <p><opt>--no-cpu-limit</opt><arg>[=BOOL]</arg></p>
 275
 276       <optdesc><p>Do not install CPU load limiter on platforms that
 277       support it. By default, PulseAudio will terminate itself when it
 278       notices that it takes up too much CPU time. This is useful as a
 279       protection against system lockups when real-time scheduling is
 280       used (see below). Disabling this mechanism is useful when
 281       debugging PulseAudio with tools like <manref name="valgrind"
 282       section="1"/> which slow down execution.</p></optdesc>
 283     </option>
 284
 285     <option>
 286       <p><opt>--disable-shm</opt><arg>[=BOOL]</arg></p>
 287
 288       <optdesc><p>PulseAudio clients and the server can exchange audio
 289       data via POSIX shared memory segments (on systems that support
 290       this). If disabled PulseAudio will communicate exclusively over
 291       sockets. Please note that data transfer via shared memory
 292       segments is always disabled when PulseAudio is running with
 293       <opt>--system</opt> enabled (see above).</p></optdesc>
 294     </option>
 295
 296     <option>
 297       <p><opt>-L | --load</opt><arg>="MODULE ARGUMENTS"</arg></p>
 298
 299       <optdesc><p>Load the specified plugin module with the specified
 300       arguments.</p></optdesc>
 301     </option>
 302
 303     <option>
 304       <p><opt>-F | --file</opt><arg>=FILENAME</arg></p>
 305
 306       <optdesc><p>Run the specified script on startup. May be
 307       specified multiple times to specify multiple scripts to be run
 308       in order. Combine with <opt>-n</opt> to disable loading of the
 309       default script <file>default.pa</file> (see below).</p></optdesc>
 310     </option>
 311     <option>
 312       <p><opt>-C</opt></p>
 313
 314       <optdesc><p>Open a command interpreter on STDIN/STDOUT after
 315       startup. This may be used to configure PulseAudio dynamically
 316       during runtime. Equivalent to
 317       <opt>--load</opt><arg>=module-cli</arg>.</p></optdesc>
 318     </option>
 319     <option>
 320       <p><opt>-n</opt></p>
 321
 322       <optdesc><p>Don't load default script file
 323       <file>default.pa</file> (see below) on startup. Useful in
 324       conjunction with <opt>-C</opt> or
 325       <opt>--file</opt>.</p></optdesc>
 326     </option>
 327
 328
 329   </options>
 330
 331   <section name="Files">
 332
 333     <p><file>~/.config/pulse/daemon.conf</file>,
 334     <file>@PA_DEFAULT_CONFIG_DIR@/daemon.conf</file>: configuration settings
 335     for the PulseAudio daemon. If the version in the user's home
 336     directory does not exist the global configuration file is
 337     loaded. See <manref name="pulse-daemon.conf" section="5"/> for
 338     more information.</p>
 339
 340     <p><file>~/.config/pulse/default.pa</file>,
 341     <file>@PA_DEFAULT_CONFIG_DIR@/default.pa</file>: the default configuration
 342     script to execute when the PulseAudio daemon is started. If the
 343     version in the user's home directory does not exist the global
 344     configuration script is loaded. See <manref name="default.pa"
 345     section="5"/> for more information.</p>
 346
 347     <p><file>~/.config/pulse/client.conf</file>,
 348     <file>@PA_DEFAULT_CONFIG_DIR@/client.conf</file>: configuration settings
 349     for PulseAudio client applications. If the version in the user's
 350     home directory does not exist the global configuration file is
 351     loaded.  See <manref name="pulse-client.conf" section="5"/> for
 352     more information.</p>
 353
 354   </section>
 355
 356   <section name="Signals">
 357
 358     <p><arg>SIGINT, SIGTERM</arg>: the PulseAudio daemon will shut
 359     down (Same as <opt>--kill</opt>).</p>
 360
 361     <p><arg>SIGHUP</arg>: dump a long status report to STDOUT or
 362     syslog, depending on the configuration.</p>
 363
 364     <p><arg>SIGUSR1</arg>: load module-cli, allowing runtime
 365     reconfiguration via STDIN/STDOUT.</p>
 366
 367     <p><arg>SIGUSR2</arg>: load module-cli-protocol-unix, allowing
 368     runtime reconfiguration via a AF_UNIX socket. See <manref
 369     name="pacmd" section="1"/> for more information.</p>
 370
 371   </section>
 372
 373   <section name="UNIX Groups and users">
 374
 375     <p>Group <arg>pulse-rt</arg>: if the PulseAudio binary is marked
 376     SUID root, then membership of the calling user in this group
 377     decides whether real-time and/or high-priority scheduling is
 378     enabled. Please note that enabling real-time scheduling is a
 379     security risk (see below).</p>
 380
 381     <p>Group <arg>pulse-access</arg>: if PulseAudio is running as a system
 382     daemon (see <opt>--system</opt> above) access is granted to
 383     members of this group when they connect via AF_UNIX sockets. If
 384     PulseAudio is running as a user daemon this group has no
 385     meaning.</p>
 386
 387     <p>User <arg>pulse</arg>, group <arg>pulse</arg>: if PulseAudio is running as a system
 388     daemon (see <opt>--system</opt> above) and is started as root the
 389     daemon will drop privileges and become a normal user process using
 390     this user and group. If PulseAudio is running as a user daemon
 391     this user and group has no meaning.</p>
 392   </section>
 393
 394   <section name="Real-time and high-priority scheduling">
 395     <p>To minimize the risk of drop-outs during playback it is
 396     recommended to run PulseAudio with real-time scheduling if the
 397     underlying platform supports it. This decouples the scheduling
 398     latency of the PulseAudio daemon from the system load and is thus
 399     the best way to make sure that PulseAudio always gets CPU time
 400     when it needs it to refill the hardware playback
 401     buffers. Unfortunately this is a security risk on most systems,
 402     since PulseAudio runs as user process, and giving realtime
 403     scheduling privileges to a user process always comes with the risk
 404     that the user misuses it to lock up the system -- which is
 405     possible since making a process real-time effectively disables
 406     preemption.</p>
 407
 408     <p>To minimize the risk PulseAudio by default does not enable
 409     real-time scheduling. It is however recommended to enable it
 410     on trusted systems. To do that start PulseAudio with
 411     <opt>--realtime</opt> (see above) or enabled the appropriate option in
 412     <file>daemon.conf</file>. Since acquiring realtime scheduling is a
 413     privileged operation on most systems, some special changes to the
 414     system configuration need to be made to allow them to the calling
 415     user. Two options are available:</p>
 416
 417     <p>On newer Linux systems the system resource limit RLIMIT_RTPRIO
 418     (see <manref name="setrlimit" section="2"/> for more information)
 419     can be used to allow specific users to acquire real-time
 420     scheduling. This can be configured in
 421     <file>/etc/security/limits.conf</file>, a resource limit of 9 is recommended.</p>
 422
 423     <p>Alternatively, the SUID root bit can be set for the PulseAudio
 424     binary. Then, the daemon will drop root privileges immediately on
 425     startup, however retain the CAP_NICE capability (on systems that
 426     support it), but only if the calling user is a member of the
 427     <arg>pulse-rt</arg> group (see above). For all other users all
 428     capabilities are dropped immediately. The advantage of this
 429     solution is that the real-time privileges are only granted to the
 430     PulseAudio daemon -- not to all the user's processes.</p>
 431
 432     <p>Alternatively, if the risk of locking up the machine is
 433     considered too big to enable real-time scheduling, high-priority
 434     scheduling can be enabled instead (i.e. negative nice level). This
 435     can be enabled by passing <opt>--high-priority</opt> (see above)
 436     when starting PulseAudio and may also be enabled with the
 437     appropriate option in <file>daemon.conf</file>. Negative nice
 438     levels can only be enabled when the appropriate resource limit
 439     RLIMIT_NICE is set (see <manref name="setrlimit" section="2"/> for
 440     more information), possibly configured in
 441     <file>/etc/security/limits.conf</file>. A resource limit of 31
 442     (corresponding with nice level -11) is recommended.</p>
 443   </section>
 444
 445   <section name="Environment variables">
 446
 447     <p>The PulseAudio client libraries check for the existence of the
 448     following environment variables and change their local configuration accordingly:</p>
 449
 450     <p><arg>$PULSE_SERVER</arg>: the server string specifying the server
 451     to connect to when a client asks for a sound server connection and doesn't
 452     explicitly ask for a specific server. The server string is a list of
 453     server addresses separated by whitespace which are tried in turn. A server
 454     address consists of an optional address type specifier (unix:, tcp:, tcp4:,
 455     tcp6:), followed by a path or host address. A host address may include an
 456     optional port number.</p>
 457
 458     <p><arg>$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>
 459
 460     <p><arg>$PULSE_SOURCE</arg>: the symbolic name of the source to connect to when a client creates a record stream and doesn't explicitly ask for a specific source.</p>
 461
 462     <p><arg>$PULSE_BINARY</arg>: path of PulseAudio executable to run when server auto-spawning is used.</p>
 463
 464     <p><arg>$PULSE_CLIENTCONFIG</arg>: path of file that shall be read instead of <file>client.conf</file> (see above) for client configuration.</p>
 465
 466     <p><arg>$PULSE_COOKIE</arg>: path of file that contains the PulseAudio
 467     authentication cookie. Defaults to <file>~/.config/pulse/cookie</file>.</p>
 468
 469     <p>These environment settings take precedence -- if set -- over the configuration settings from <file>client.conf</file> (see above).</p>
 470
 471   </section>
 472
 473   <section name="Authors">
 474     <p>The PulseAudio Developers &lt;@PACKAGE_BUGREPORT@&gt;; PulseAudio is available from <url href="@PACKAGE_URL@"/></p>
 475   </section>
 476
 477   <section name="See also">
 478     <p>
 479       <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"/>
 480     </p>
 481   </section>
 482
 483 </manpage>