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