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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,stderr,file: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>file:PATH</arg>, logging is directed to
 226       the file indicated by PATH.</p></optdesc>
 227     </option>
 228
 229     <option>
 230       <p><opt>--log-meta</opt><arg>[=BOOL]</arg></p>
 231
 232       <optdesc><p>Show source code location in log messages.</p></optdesc>
 233     </option>
 234
 235     <option>
 236       <p><opt>--log-time</opt><arg>[=BOOL]</arg></p>
 237
 238       <optdesc><p>Show timestamps in log messages.</p></optdesc>
 239     </option>
 240
 241     <option>
 242       <p><opt>--log-backtrace</opt><arg>=FRAMES</arg></p>
 243
 244       <optdesc><p>When FRAMES is greater than 0, log for each message a
 245       stack trace up to the number of specified stack frames.</p></optdesc>
 246     </option>
 247
 248     <option>
 249       <p><opt>--p | --dl-search-path</opt><arg>=PATH</arg></p>
 250
 251       <optdesc><p>Set the search path for dynamic shared objects
 252       (plugins).</p></optdesc>
 253     </option>
 254
 255     <option>
 256       <p><opt>--resample-method</opt><arg>=METHOD</arg></p>
 257
 258       <optdesc><p>Use the specified resampler by default (See
 259       <opt>--dump-resample-methods</opt> above for possible
 260       values).</p></optdesc>
 261     </option>
 262
 263     <option>
 264       <p><opt>--use-pid-file</opt><arg>[=BOOL]</arg></p>
 265
 266       <optdesc><p>Create a PID file. If this options is disabled it is possible to run multiple sound servers per user.</p></optdesc>
 267     </option>
 268
 269     <option>
 270       <p><opt>--no-cpu-limit</opt><arg>[=BOOL]</arg></p>
 271
 272       <optdesc><p>Do not install CPU load limiter on platforms that
 273       support it. By default, PulseAudio will terminate itself when it
 274       notices that it takes up too much CPU time. This is useful as a
 275       protection against system lockups when real-time scheduling is
 276       used (see below). Disabling this meachnism is useful when
 277       debugging PulseAudio with tools like <manref name="valgrind"
 278       section="1"/> which slow down execution.</p></optdesc>
 279     </option>
 280
 281     <option>
 282       <p><opt>--disable-shm</opt><arg>[=BOOL]</arg></p>
 283
 284       <optdesc><p>PulseAudio clients and the server can exchange audio
 285       data via POSIX shared memory segments (on systems that support
 286       this). If disabled PulseAudio will communicate exclusively over
 287       sockets. Please note that data transfer via shared memory
 288       segments is always disabled when PulseAudio is running with
 289       <opt>--system</opt> enabled (see above).</p></optdesc>
 290     </option>
 291
 292     <option>
 293       <p><opt>-L | --load</opt><arg>="MODULE ARGUMENTS"</arg></p>
 294
 295       <optdesc><p>Load the specified plugin module with the specified
 296       arguments.</p></optdesc>
 297     </option>
 298
 299     <option>
 300       <p><opt>-F | --file</opt><arg>=FILENAME</arg></p>
 301
 302       <optdesc><p>Run the specified script on startup. May be
 303       specified multiple times to specify multiple scripts to be run
 304       in order. Combine with <opt>-n</opt> to disable loading of the
 305       default script <file>default.pa</file> (see below).</p></optdesc>
 306     </option>
 307     <option>
 308       <p><opt>-C</opt></p>
 309
 310       <optdesc><p>Open a command interpreter on STDIN/STDOUT after
 311       startup. This may be used to configure PulseAudio dynamically
 312       during runtime. Equivalent to
 313       <opt>--load</opt><arg>=module-cli</arg>.</p></optdesc>
 314     </option>
 315     <option>
 316       <p><opt>-n</opt></p>
 317
 318       <optdesc><p>Don't load default script file
 319       <file>default.pa</file> (see below) on startup. Useful in
 320       conjunction with <opt>-C</opt> or
 321       <opt>--file</opt>.</p></optdesc>
 322     </option>
 323
 324
 325   </options>
 326
 327   <section name="Files">
 328
 329     <p><file>~/.config/pulse/daemon.conf</file>,
 330     <file>@PA_DEFAULT_CONFIG_DIR@/daemon.conf</file>: configuration settings
 331     for the PulseAudio daemon. If the version in the user's home
 332     directory does not exist the global configuration file is
 333     loaded. See <manref name="pulse-daemon.conf" section="5"/> for
 334     more information.</p>
 335
 336     <p><file>~/.config/pulse/default.pa</file>,
 337     <file>@PA_DEFAULT_CONFIG_DIR@/default.pa</file>: the default configuration
 338     script to execute when the PulseAudio daemon is started. If the
 339     version in the user's home directory does not exist the global
 340     configuration script is loaded. See <manref name="default.pa"
 341     section="5"/> for more information.</p>
 342
 343     <p><file>~/.config/pulse/client.conf</file>,
 344     <file>@PA_DEFAULT_CONFIG_DIR@/client.conf</file>: configuration settings
 345     for PulseAudio client applications. If the version in the user's
 346     home directory does not exist the global configuration file is
 347     loaded.  See <manref name="pulse-client.conf" section="5"/> for
 348     more information.</p>
 349
 350   </section>
 351
 352   <section name="Signals">
 353
 354     <p><arg>SIGINT, SIGTERM</arg>: the PulseAudio daemon will shut
 355     down (Same as <opt>--kill</opt>).</p>
 356
 357     <p><arg>SIGHUP</arg>: dump a long status report to STDOUT or
 358     syslog, depending on the configuration.</p>
 359
 360     <p><arg>SIGUSR1</arg>: load module-cli, allowing runtime
 361     reconfiguration via STDIN/STDOUT.</p>
 362
 363     <p><arg>SIGUSR2</arg>: load module-cli-protocol-unix, allowing
 364     runtime reconfiguration via a AF_UNIX socket. See <manref
 365     name="pacmd" section="1"/> for more information.</p>
 366
 367   </section>
 368
 369   <section name="UNIX Groups and users">
 370
 371     <p>Group <arg>pulse-rt</arg>: if the PulseAudio binary is marked
 372     SUID root, then membership of the calling user in this group
 373     decides whether real-time and/or high-priority scheduling is
 374     enabled. Please note that enabling real-time scheduling is a
 375     security risk (see below).</p>
 376
 377     <p>Group <arg>pulse-access</arg>: if PulseAudio is running as a system
 378     daemon (see <opt>--system</opt> above) access is granted to
 379     members of this group when they connect via AF_UNIX sockets. If
 380     PulseAudio is running as a user daemon this group has no
 381     meaning.</p>
 382
 383     <p>User <arg>pulse</arg>, group <arg>pulse</arg>: if PulseAudio is running as a system
 384     daemon (see <opt>--system</opt> above) and is started as root the
 385     daemon will drop priviliges and become a normal user process using
 386     this user and group. If PulseAudio is running as a user daemon
 387     this user and group has no meaning.</p>
 388   </section>
 389
 390   <section name="Real-time and high-priority scheduling">
 391     <p>To minimize the risk of drop-outs during playback it is
 392     recommended to run PulseAudio with real-time scheduling if the
 393     underlying platform supports it. This decouples the scheduling
 394     latency of the PulseAudio daemon from the system load and is thus
 395     the best way to make sure that PulseAudio always gets CPU time
 396     when it needs it to refill the hardware playback
 397     buffers. Unfortunately this is a security risk on most systems,
 398     since PulseAudio runs as user process, and giving realtime
 399     scheduling priviliges to a user process always comes with the risk
 400     that the user misuses it to lock up the system -- which is
 401     possible since making a process real-time effectively disables
 402     preemption.</p>
 403
 404     <p>To minimize the risk PulseAudio by default does not enable
 405     real-time scheduling. It is however recommended to enable it
 406     on trusted systems. To do that start PulseAudio with
 407     <opt>--realtime</opt> (see above) or enabled the appropriate option in
 408     <file>daemon.conf</file>. Since acquiring realtime scheduling is a
 409     priviliged operation on most systems, some special changes to the
 410     system configuration need to be made to allow them to the calling
 411     user. Two options are available:</p>
 412
 413     <p>On newer Linux systems the system resource limit RLIMIT_RTPRIO
 414     (see <manref name="setrlimit" section="2"/> for more information)
 415     can be used to allow specific users to acquire real-time
 416     scheduling. This can be configured in
 417     <file>/etc/security/limits.conf</file>, a resource limit of 9 is recommended.</p>
 418
 419     <p>Alternatively, the SUID root bit can be set for the PulseAudio
 420     binary. Then, the daemon will drop root priviliges immediately on
 421     startup, however retain the CAP_NICE capability (on systems that
 422     support it), but only if the calling user is a member of the
 423     <arg>pulse-rt</arg> group (see above). For all other users all
 424     capababilities are dropped immediately. The advantage of this
 425     solution is that the real-time priviliges are only granted to the
 426     PulseAudio daemon -- not to all the user's processes.</p>
 427
 428     <p>Alternatively, if the risk of locking up the machine is
 429     considered too big to enable real-time scheduling, high-priority
 430     scheduling can be enabled instead (i.e. negative nice level). This
 431     can be enabled by passing <opt>--high-priority</opt> (see above)
 432     when starting PulseAudio and may also be enabled with the
 433     approriate option in <file>daemon.conf</file>. Negative nice
 434     levels can only be enabled when the appropriate resource limit
 435     RLIMIT_NICE is set (see <manref name="setrlimit" section="2"/> for
 436     more information), possibly configured in
 437     <file>/etc/security/limits.conf</file>. A resource limit of 31
 438     (corresponding with nice level -11) is recommended.</p>
 439   </section>
 440
 441   <section name="Environment variables">
 442
 443     <p>The PulseAudio client libraries check for the existance of the
 444     following environment variables and change their local configuration accordingly:</p>
 445
 446     <p><arg>$PULSE_SERVER</arg>: the server string specifying the server to connect to when a client asks for a sound server connection and doesn't explicitly ask for a specific server.</p>
 447
 448     <p><arg>$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>
 449
 450     <p><arg>$PULSE_SOURCE</arg>: the symbolic name of the source to connect to when a client creates a record stream and doesn't explicitly ask for a specific source.</p>
 451
 452     <p><arg>$PULSE_BINARY</arg>: path of PulseAudio executable to run when server auto-spawning is used.</p>
 453
 454     <p><arg>$PULSE_CLIENTCONFIG</arg>: path of file that shall be read instead of <file>client.conf</file> (see above) for client configuration.</p>
 455
 456     <p>These environment settings take precedence -- if set -- over the configuration settings from <file>client.conf</file> (see above).</p>
 457
 458   </section>
 459
 460   <section name="Authors">
 461     <p>The PulseAudio Developers &lt;@PACKAGE_BUGREPORT@&gt;; PulseAudio is available from <url href="@PACKAGE_URL@"/></p>
 462   </section>
 463
 464   <section name="See also">
 465     <p>
 466       <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"/>
 467     </p>
 468   </section>
 469
 470 </manpage>