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