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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>--disallow-exit</opt><arg>[=BOOL]</arg></p>
 185
 186       <optdesc><p>Disallow user requested exit</p></optdesc>
 187     </option>
 188
 189     <option>
 190       <p><opt>--exit-idle-time</opt><arg>=SECS</arg></p>
 191
 192       <optdesc><p>Terminate the daemon when idle and the specified
 193       number of seconds passed.</p></optdesc>
 194     </option>
 195
 196     <option>
 197       <p><opt>--scache-idle-time</opt><arg>=SECS</arg></p>
 198
 199       <optdesc><p>Unload autoloaded samples from the cache when the
 200       haven't been used for the specified number of
 201       seconds.</p></optdesc>
 202     </option>
 203
 204     <option>
 205       <p><opt>--log-level</opt><arg>[=LEVEL]</arg></p>
 206
 207       <optdesc><p>If an argument is passed, set the log level to the
 208       specified value, otherwise increase the configured verbosity
 209       level by one. The log levels are numerical from 0 to 4,
 210       corresponding to <arg>error</arg>, <arg>warn</arg>,
 211       <arg>notice</arg>, <arg>info</arg>, <arg>debug</arg>. Default
 212       log level is <arg>notice</arg>, i.e. all log messages with lower
 213       log levels are printed: <arg>error</arg>, <arg>warn</arg>,
 214       <arg>notice</arg>.</p></optdesc>
 215     </option>
 216
 217     <option>
 218       <p><opt>-v | --verbose</opt></p>
 219
 220       <optdesc><p>Increase the configured verbosity level by one (see
 221       <opt>--log-level</opt> above). Specify multiple times to
 222       increase log level multiple times.</p></optdesc>
 223     </option>
 224
 225     <option>
 226       <p><opt>--log-target</opt><arg>={auto,syslog,journal,stderr,file:PATH,newfile:PATH}</arg></p>
 227
 228       <optdesc><p>Specify the log target. If set to <arg>auto</arg>
 229       (which is the default), then logging is directed to syslog when
 230       <opt>--daemonize</opt> is passed, otherwise to
 231       STDERR. If set to <arg>journal</arg> logging is directed to the systemd
 232       journal. If set to <arg>file:PATH</arg>, logging is directed to
 233       the file indicated by PATH. <arg>newfile:PATH</arg> is otherwise
 234       the same as file:PATH, but existing files are never overwritten.
 235       If the specified file already exists, a suffix is added to the
 236       file name to avoid overwriting.</p></optdesc>
 237     </option>
 238
 239     <option>
 240       <p><opt>--log-meta</opt><arg>[=BOOL]</arg></p>
 241
 242       <optdesc><p>Show source code location in log messages.</p></optdesc>
 243     </option>
 244
 245     <option>
 246       <p><opt>--log-time</opt><arg>[=BOOL]</arg></p>
 247
 248       <optdesc><p>Show timestamps in log messages.</p></optdesc>
 249     </option>
 250
 251     <option>
 252       <p><opt>--log-backtrace</opt><arg>=FRAMES</arg></p>
 253
 254       <optdesc><p>When FRAMES is greater than 0, log for each message a
 255       stack trace up to the number of specified stack frames.</p></optdesc>
 256     </option>
 257
 258     <option>
 259       <p><opt>-p | --dl-search-path</opt><arg>=PATH</arg></p>
 260
 261       <optdesc><p>Set the search path for dynamic shared objects
 262       (plugins).</p></optdesc>
 263     </option>
 264
 265     <option>
 266       <p><opt>--resample-method</opt><arg>=METHOD</arg></p>
 267
 268       <optdesc><p>Use the specified resampler by default (See
 269       <opt>--dump-resample-methods</opt> above for possible
 270       values).</p></optdesc>
 271     </option>
 272
 273     <option>
 274       <p><opt>--use-pid-file</opt><arg>[=BOOL]</arg></p>
 275
 276       <optdesc><p>Create a PID file. If this options is disabled it is possible to run multiple sound servers per user.</p></optdesc>
 277     </option>
 278
 279     <option>
 280       <p><opt>--no-cpu-limit</opt><arg>[=BOOL]</arg></p>
 281
 282       <optdesc><p>Do not install CPU load limiter on platforms that
 283       support it. By default, PulseAudio will terminate itself when it
 284       notices that it takes up too much CPU time. This is useful as a
 285       protection against system lockups when real-time scheduling is
 286       used (see below). Disabling this mechanism is useful when
 287       debugging PulseAudio with tools like <manref name="valgrind"
 288       section="1"/> which slow down execution.</p></optdesc>
 289     </option>
 290
 291     <option>
 292       <p><opt>--disable-shm</opt><arg>[=BOOL]</arg></p>
 293
 294       <optdesc><p>PulseAudio clients and the server can exchange audio
 295       data via POSIX shared memory segments (on systems that support
 296       this). If disabled PulseAudio will communicate exclusively over
 297       sockets. Please note that data transfer via shared memory
 298       segments is always disabled when PulseAudio is running with
 299       <opt>--system</opt> enabled (see above).</p></optdesc>
 300     </option>
 301
 302     <option>
 303       <p><opt>-L | --load</opt><arg>="MODULE ARGUMENTS"</arg></p>
 304
 305       <optdesc><p>Load the specified plugin module with the specified
 306       arguments.</p></optdesc>
 307     </option>
 308
 309     <option>
 310       <p><opt>-F | --file</opt><arg>=FILENAME</arg></p>
 311
 312       <optdesc><p>Run the specified script on startup. May be
 313       specified multiple times to specify multiple scripts to be run
 314       in order. Combine with <opt>-n</opt> to disable loading of the
 315       default script <file>default.pa</file> (see below).</p></optdesc>
 316     </option>
 317     <option>
 318       <p><opt>-C</opt></p>
 319
 320       <optdesc><p>Open a command interpreter on STDIN/STDOUT after
 321       startup. This may be used to configure PulseAudio dynamically
 322       during runtime. Equivalent to
 323       <opt>--load</opt><arg>=module-cli</arg>.</p></optdesc>
 324     </option>
 325     <option>
 326       <p><opt>-n</opt></p>
 327
 328       <optdesc><p>Don't load default script file
 329       <file>default.pa</file> (see below) on startup. Useful in
 330       conjunction with <opt>-C</opt> or
 331       <opt>--file</opt>.</p></optdesc>
 332     </option>
 333
 334
 335   </options>
 336
 337   <section name="Files">
 338
 339     <p><file>~/.config/pulse/daemon.conf</file>,
 340     <file>@PA_DEFAULT_CONFIG_DIR@/daemon.conf</file>: configuration settings
 341     for the PulseAudio daemon. If the version in the user's home
 342     directory does not exist the global configuration file is
 343     loaded. See <manref name="pulse-daemon.conf" section="5"/> for
 344     more information.</p>
 345
 346     <p><file>~/.config/pulse/default.pa</file>,
 347     <file>@PA_DEFAULT_CONFIG_DIR@/default.pa</file>: the default configuration
 348     script to execute when the PulseAudio daemon is started. If the
 349     version in the user's home directory does not exist the global
 350     configuration script is loaded. See <manref name="default.pa"
 351     section="5"/> for more information.</p>
 352
 353     <p><file>~/.config/pulse/client.conf</file>,
 354     <file>@PA_DEFAULT_CONFIG_DIR@/client.conf</file>: configuration settings
 355     for PulseAudio client applications. If the version in the user's
 356     home directory does not exist the global configuration file is
 357     loaded.  See <manref name="pulse-client.conf" section="5"/> for
 358     more information.</p>
 359
 360   </section>
 361
 362   <section name="Signals">
 363
 364     <p><arg>SIGINT, SIGTERM</arg>: the PulseAudio daemon will shut
 365     down (Same as <opt>--kill</opt>).</p>
 366
 367     <p><arg>SIGHUP</arg>: dump a long status report to STDOUT or
 368     syslog, depending on the configuration.</p>
 369
 370     <p><arg>SIGUSR1</arg>: load module-cli, allowing runtime
 371     reconfiguration via STDIN/STDOUT.</p>
 372
 373     <p><arg>SIGUSR2</arg>: load module-cli-protocol-unix, allowing
 374     runtime reconfiguration via a AF_UNIX socket. See <manref
 375     name="pacmd" section="1"/> for more information.</p>
 376
 377   </section>
 378
 379   <section name="UNIX Groups and users">
 380
 381     <p>Group <arg>pulse-rt</arg>: if the PulseAudio binary is marked
 382     SUID root, then membership of the calling user in this group
 383     decides whether real-time and/or high-priority scheduling is
 384     enabled. Please note that enabling real-time scheduling is a
 385     security risk (see below).</p>
 386
 387     <p>Group <arg>pulse-access</arg>: if PulseAudio is running as a system
 388     daemon (see <opt>--system</opt> above) access is granted to
 389     members of this group when they connect via AF_UNIX sockets. If
 390     PulseAudio is running as a user daemon this group has no
 391     meaning.</p>
 392
 393     <p>User <arg>pulse</arg>, group <arg>pulse</arg>: if PulseAudio is running as a system
 394     daemon (see <opt>--system</opt> above) and is started as root the
 395     daemon will drop privileges and become a normal user process using
 396     this user and group. If PulseAudio is running as a user daemon
 397     this user and group has no meaning.</p>
 398   </section>
 399
 400   <section name="Real-time and high-priority scheduling">
 401     <p>To minimize the risk of drop-outs during playback it is
 402     recommended to run PulseAudio with real-time scheduling if the
 403     underlying platform supports it. This decouples the scheduling
 404     latency of the PulseAudio daemon from the system load and is thus
 405     the best way to make sure that PulseAudio always gets CPU time
 406     when it needs it to refill the hardware playback
 407     buffers. Unfortunately this is a security risk on most systems,
 408     since PulseAudio runs as user process, and giving realtime
 409     scheduling privileges to a user process always comes with the risk
 410     that the user misuses it to lock up the system -- which is
 411     possible since making a process real-time effectively disables
 412     preemption.</p>
 413
 414     <p>To minimize the risk PulseAudio by default does not enable
 415     real-time scheduling. It is however recommended to enable it
 416     on trusted systems. To do that start PulseAudio with
 417     <opt>--realtime</opt> (see above) or enabled the appropriate option in
 418     <file>daemon.conf</file>. Since acquiring realtime scheduling is a
 419     privileged operation on most systems, some special changes to the
 420     system configuration need to be made to allow them to the calling
 421     user. Two options are available:</p>
 422
 423     <p>On newer Linux systems the system resource limit RLIMIT_RTPRIO
 424     (see <manref name="setrlimit" section="2"/> for more information)
 425     can be used to allow specific users to acquire real-time
 426     scheduling. This can be configured in
 427     <file>/etc/security/limits.conf</file>, a resource limit of 9 is recommended.</p>
 428
 429     <p>Alternatively, the SUID root bit can be set for the PulseAudio
 430     binary. Then, the daemon will drop root privileges immediately on
 431     startup, however retain the CAP_NICE capability (on systems that
 432     support it), but only if the calling user is a member of the
 433     <arg>pulse-rt</arg> group (see above). For all other users all
 434     capabilities are dropped immediately. The advantage of this
 435     solution is that the real-time privileges are only granted to the
 436     PulseAudio daemon -- not to all the user's processes.</p>
 437
 438     <p>Alternatively, if the risk of locking up the machine is
 439     considered too big to enable real-time scheduling, high-priority
 440     scheduling can be enabled instead (i.e. negative nice level). This
 441     can be enabled by passing <opt>--high-priority</opt> (see above)
 442     when starting PulseAudio and may also be enabled with the
 443     appropriate option in <file>daemon.conf</file>. Negative nice
 444     levels can only be enabled when the appropriate resource limit
 445     RLIMIT_NICE is set (see <manref name="setrlimit" section="2"/> for
 446     more information), possibly configured in
 447     <file>/etc/security/limits.conf</file>. A resource limit of 31
 448     (corresponding with nice level -11) is recommended.</p>
 449   </section>
 450
 451   <section name="Environment variables">
 452
 453     <p>The PulseAudio client libraries check for the existence of the
 454     following environment variables and change their local configuration accordingly:</p>
 455
 456     <p><arg>$PULSE_SERVER</arg>: the server string specifying the server
 457     to connect to when a client asks for a sound server connection and doesn't
 458     explicitly ask for a specific server. The server string is a list of
 459     server addresses separated by whitespace which are tried in turn. A server
 460     address consists of an optional address type specifier (unix:, tcp:, tcp4:,
 461     tcp6:), followed by a path or host address. A host address may include an
 462     optional port number.</p>
 463
 464     <p><arg>$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>
 465
 466     <p><arg>$PULSE_SOURCE</arg>: the symbolic name of the source to connect to when a client creates a record stream and doesn't explicitly ask for a specific source.</p>
 467
 468     <p><arg>$PULSE_BINARY</arg>: path of PulseAudio executable to run when server auto-spawning is used.</p>
 469
 470     <p><arg>$PULSE_CLIENTCONFIG</arg>: path of file that shall be read instead of <file>client.conf</file> (see above) for client configuration.</p>
 471
 472     <p><arg>$PULSE_COOKIE</arg>: path of file that contains the PulseAudio
 473     authentication cookie. Defaults to <file>~/.config/pulse/cookie</file>.</p>
 474
 475     <p>These environment settings take precedence -- if set -- over the configuration settings from <file>client.conf</file> (see above).</p>
 476
 477   </section>
 478
 479   <section name="Authors">
 480     <p>The PulseAudio Developers &lt;@PACKAGE_BUGREPORT@&gt;; PulseAudio is available from <url href="@PACKAGE_URL@"/></p>
 481   </section>
 482
 483   <section name="See also">
 484     <p>
 485       <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"/>
 486     </p>
 487   </section>
 488
 489 </manpage>