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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-resampe-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.</p></optdesc>
 114     </option>
 115
 116
 117     <option>
 118       <p><opt>--system</opt><arg>[=BOOL]</arg></p>
 119
 120       <optdesc><p>Run as system-wide instance instead of
 121       per-user. Please not that this disables certain features of
 122       PulseAudio and is generally not recommended unless the system
 123       knows no local users (e.g. is a thin client). This feature needs
 124       special configuration and a dedicated UNIX user set up. It is
 125       highly recommended to combine this with
 126       <opt>--disallow-module-loading</opt> (see below).</p></optdesc>
 127     </option>
 128
 129     <option>
 130       <p><opt>-D | --daemon</opt><arg>[=BOOL]</arg></p>
 131
 132       <optdesc><p>Daemonize after startup, i.e. detach from the
 133       terminal.</p></optdesc>
 134     </option>
 135
 136     <option>
 137       <p><opt>--fail</opt><arg>[=BOOL]</arg></p>
 138
 139       <optdesc><p>Fail startup when any of the commands specified in
 140       the startup script <file>default.pa</file> (see below)
 141       fails.</p></optdesc>
 142     </option>
 143
 144     <option>
 145       <p><opt>--high-priority</opt><arg>[=BOOL]</arg></p>
 146
 147       <optdesc><p>Try to acquire a high Unix nice level. This will
 148       only succeed if the calling user has a non-zero RLIMIT_NICE
 149       resource limit set (on systems that support this), or we're
 150       called SUID root (see below), or we are configure to be run as
 151       system daemon (see <arg>--system</arg> above). It is recommended
 152       to enable this, since it is only a negligible security risk (see
 153       below).</p></optdesc>
 154     </option>
 155
 156     <option>
 157       <p><opt>--realtime</opt><arg>[=BOOL]</arg></p>
 158
 159       <optdesc><p>Try to acquire a real-time scheduling for
 160       PulseAudio's I/O threads. This will only succeed if the calling
 161       user has a non-zero RLIMIT_RTPRIO resource limit set (on systems
 162       that support this), or we're called SUID root (see below), or we
 163       are configure to be run as system daemon (see
 164       <arg>--system</arg> above). It is recommended to enable this
 165       only for trusted users, since it is a major security risk (see
 166       below).</p></optdesc>
 167     </option>
 168
 169     <option>
 170       <p><opt>--disallow-module-loading</opt><arg>[=BOOL]</arg></p>
 171
 172       <optdesc><p>Disallow module loading after startup. This is a
 173       security feature since it disallows additional module loading
 174       during runtime and on user request. It is highly recommended
 175       when <arg>--system</arg> is used (see above). Note however, that
 176       this breaks certain features like automatic module loading on hot
 177       plug.</p></optdesc>
 178
 179     </option>
 180
 181     <option>
 182       <p><opt>--exit-idle-time</opt><arg>=SECS</arg></p>
 183
 184       <optdesc><p>Terminate the daemon when idle and the specified
 185       number of seconds passed.</p></optdesc>
 186     </option>
 187
 188     <option>
 189       <p><opt>--module-idle-time</opt><arg>=SECS</arg></p>
 190
 191       <optdesc><p>Unload autoloaded modules when idle and the
 192       specified number of seconds passed.</p></optdesc>
 193     </option>
 194
 195     <option>
 196       <p><opt>--scache-idle-time</opt><arg>=SECS</arg></p>
 197
 198       <optdesc><p>Unload autoloaded samples from the cache when the
 199       haven't been used for the specified number of
 200       seconds.</p></optdesc>
 201     </option>
 202
 203     <option>
 204       <p><opt>--log-level</opt><arg>[=LEVEL]</arg></p>
 205
 206       <optdesc><p>If an argument is passed, set the log level to the
 207       specified value, otherwise increase the configured verbosity
 208       level by one. The log levels are numerical from 0 to 4,
 209       corresponding to <arg>error</arg>, <arg>warn</arg>,
 210       <arg>notice</arg>, <arg>info</arg>, <arg>debug</arg>. Default
 211       log level is <arg>notice</arg>, i.e. all log messages with lower
 212       log levels are printed: <arg>error</arg>, <arg>warn</arg>,
 213       <arg>notice</arg>.</p></optdesc>
 214     </option>
 215
 216     <option>
 217       <p><opt>-v</opt></p>
 218
 219       <optdesc><p>Increase the configured verbosity level by one (see
 220       <opt>--log-level</opt> above). Specify multiple times to
 221       increase log level multiple times.</p></optdesc>
 222     </option>
 223
 224     <option>
 225       <p><opt>--log-target</opt><arg>={auto,syslog,stderr}</arg></p>
 226
 227       <optdesc><p>Specify the log target. If set to <arg>auto</arg>
 228       (which is the default), then logging is directed to syslog when
 229       <opt>--daemonize</opt> is passed, otherwise to
 230       STDERR.</p></optdesc>
 231     </option>
 232
 233     <option>
 234       <p><opt>--p | --dl-search-path</opt><arg>=PATH</arg></p>
 235
 236       <optdesc><p>Set the search path for dynamic shared objects
 237       (plugins).</p></optdesc>
 238     </option>
 239
 240     <option>
 241       <p><opt>--resample-method</opt><arg>=METHOD</arg></p>
 242
 243       <optdesc><p>Use the specified resampler by default (See
 244       <opt>--dump-resample-methods</opt> above for possible
 245       values).</p></optdesc>
 246     </option>
 247
 248     <option>
 249       <p><opt>--use-pid-file</opt><arg>[=BOOL]</arg></p>
 250
 251       <optdesc><p>Create a PID file. If this options is disabled it is possible to run multiple sound servers per user.</p></optdesc>
 252     </option>
 253
 254     <option>
 255       <p><opt>--no-cpu-limit</opt><arg>[=BOOL]</arg></p>
 256
 257       <optdesc><p>Do not install CPU load limiter on platforms that
 258       support it. By default, PulseAudio will terminate itself when it
 259       notices that it takes up too much CPU time. This is useful as a
 260       protection against system lockups when real-time scheduling is
 261       used (see below). Disabling this meachnism is useful when
 262       debugging PulseAudio with tools like <manref name="valgrind"
 263       section="1"/> which slow down execution.</p></optdesc>
 264     </option>
 265
 266     <option>
 267       <p><opt>--disable-shm</opt><arg>[=BOOL]</arg></p>
 268
 269       <optdesc><p>PulseAudio clients and the server can exchange audio
 270       data via POSIX shared memory segments (on systems that support
 271       this). If disabled PulseAudio will communicate exclusively over
 272       sockets. Please note that data transfer via shared memory
 273       segments is always disabled when PulseAudio is running with
 274       <opt>--system</opt> enabled (see above).</p></optdesc>
 275     </option>
 276
 277     <option>
 278       <p><opt>-L | --load</opt><arg>="MODULE ARGUMENTS"</arg></p>
 279
 280       <optdesc><p>Load the specified plugin module with the specified
 281       arguments.</p></optdesc>
 282     </option>
 283
 284     <option>
 285       <p><opt>-F | --file</opt><arg>=FILENAME</arg></p>
 286
 287       <optdesc><p>Run the specified script on startup. May be
 288       specified multiple times to specify multiple scripts to be run
 289       in order. Combine with <opt>-n</opt> to disable loading of the
 290       default script <file>default.pa</file> (see below).</p></optdesc>
 291     </option>
 292     <option>
 293       <p><opt>-C</opt></p>
 294
 295       <optdesc><p>Open a command interpreter on STDIN/STDOUT after
 296       startup. This may be used to configure PulseAudio dynamically
 297       during runtime. Equivalent to
 298       <opt>--load</opt><arg>=module-cli</arg>.</p></optdesc>
 299     </option>
 300     <option>
 301       <p><opt>-n</opt></p>
 302
 303       <optdesc><p>Don't load default script file
 304       <file>default.pa</file> (see below) on startup. Useful in
 305       conjunction with <opt>-C</opt> or
 306       <opt>--file</opt>.</p></optdesc>
 307     </option>
 308
 309
 310   </options>
 311
 312   <section name="Files">
 313
 314     <p><file>~/.pulse/daemon.conf</file>,
 315     <file>@pulseconfdir@/daemon.conf</file>: configuration settings
 316     for the PulseAudio daemon. If the version in the user's home
 317     directory does not exist the global configuration file is
 318     loaded. See <manref name="pulse-daemon.conf" section="5"/> for
 319     more information.</p>
 320
 321     <p><file>~/.pulse/default.pa</file>,
 322     <file>@pulseconfdir@/default.pa</file>: the default configuration
 323     script to execute when the PulseAudio daemon is started. If the
 324     version in the user's home directory does not exist the global
 325     configuration script is loaded. See <manref name="default.pa"
 326     section="5"/> for more information.</p>
 327
 328     <p><file>~/.pulse/client.conf</file>,
 329     <file>@pulseconfdir@/client.conf</file>: configuration settings
 330     for PulseAudio client applications. If the version in the user's
 331     home directory does not exist the global configuration file is
 332     loaded.  See <manref name="pulse-client.conf" section="5"/> for
 333     more information.</p>
 334
 335   </section>
 336
 337   <section name="Signals">
 338
 339     <p><arg>SIGINT, SIGTERM</arg>: the PulseAudio daemon will shut
 340     down (Same as <opt>--kill</opt>).</p>
 341
 342     <p><arg>SIGHUP</arg>: dump a long status report to STDOUT or
 343     syslog, depending on the configuration.</p>
 344
 345     <p><arg>SIGUSR1</arg>: load module-cli, allowing runtime
 346     reconfiguration via STDIN/STDOUT.</p>
 347
 348     <p><arg>SIGUSR2</arg>: load module-cli-protocol-unix, allowing
 349     runtime reconfiguration via a AF_UNIX socket. See <manref
 350     name="pacmd" section="1"/> for more information.</p>
 351
 352   </section>
 353
 354   <section name="UNIX Groups and users">
 355
 356     <p>Group <arg>pulse-rt</arg>: if the PulseAudio binary is marked
 357     SUID root, then membership of the calling user in this group
 358     decides whether real-time and/or high-priority scheduling is
 359     enabled. Please note that enabling real-time scheduling is a
 360     security risk (see below).</p>
 361
 362     <p>Group <arg>pulse-access</arg>: if PulseAudio is running as a system
 363     daemon (see <opt>--system</opt> above) access is granted to
 364     members of this group when they connect via AF_UNIX sockets. If
 365     PulseAudio is running as a user daemon this group has no
 366     meaning.</p>
 367
 368     <p>User <arg>pulse</arg>, group <arg>pulse</arg>: if PulseAudio is running as a system
 369     daemon (see <opt>--system</opt> above) and is started as root the
 370     daemon will drop priviliges and become a normal user process using
 371     this user and group. If PulseAudio is running as a user daemon
 372     this user and group has no meaning.</p>
 373   </section>
 374
 375   <section name="Real-time and high-priority scheduling">
 376     <p>To minimize the risk of drop-outs during playback it is
 377     recommended to run PulseAudio with real-time scheduling if the
 378     underlying platform supports it. This decouples the scheduling
 379     latency of the PulseAudio daemon from the system load and is thus
 380     the best way to make sure that PulseAudio always gets CPU time
 381     when it needs it to refill the hardware playback
 382     buffers. Unfortunately this is a security risk on most systems,
 383     since PulseAudio runs as user process, and giving realtime
 384     scheduling priviliges to a user process always comes with the risk
 385     that the user misuses it to lock up the system -- which is
 386     possible since making a process real-time effectively disables
 387     preemption.</p>
 388
 389     <p>To minimize the risk PulseAudio by default does not enable
 390     real-time scheduling. It is however recommended to enable it
 391     on trusted systems. To do that start PulseAudio with
 392     <opt>--realtime</opt> (see above) or enabled the appropriate option in
 393     <file>daemon.conf</file>. Since acquiring realtime scheduling is a
 394     priviliged operation on most systems, some special changes to the
 395     system configuration need to be made to allow them to the calling
 396     user. Two options are available:</p>
 397
 398     <p>On newer Linux systems the system resource limit RLIMIT_RTPRIO
 399     (see <manref name="setrlimit" section="2"/> for more information)
 400     can be used to allow specific users to acquire real-time
 401     scheduling. This can be configured in
 402     <file>/etc/security/limits.conf</file>, a resource limit of 9 is recommended.</p>
 403
 404     <p>Alternatively, the SUID root bit can be set for the PulseAudio
 405     binary. Then, the daemon will drop root priviliges immediately on
 406     startup, however retain the CAP_NICE capability (on systems that
 407     support it), but only if the calling user is a member of the
 408     <arg>pulse-rt</arg> group (see above). For all other users all
 409     capababilities are dropped immediately. The advantage of this
 410     solution is that the real-time priviliges are only granted to the
 411     PulseAudio daemon -- not to all the user's processes.</p>
 412
 413     <p>Alternatively, if the risk of locking up the machine is
 414     considered too big to enable real-time scheduling, high-priority
 415     scheduling can be enabled instead (i.e. negative nice level). This
 416     can be enabled by passing <opt>--high-priority</opt> (see above)
 417     when starting PulseAudio and may also be enabled with the
 418     approriate option in <file>daemon.conf</file>. Negative nice
 419     levels can only be enabled when the appropriate resource limit
 420     RLIMIT_NICE is set (see <manref name="setrlimit" section="2"/> for
 421     more information), possibly configured in
 422     <file>/etc/security/limits.conf</file>. A resource limit of 31
 423     (corresponding with nice level -11) is recommended.</p>
 424   </section>
 425
 426   <section name="Environment variables">
 427
 428     <p>The PulseAudio client libraries check for the existance of the
 429     following environment variables and change their local configuration accordingly:</p>
 430
 431     <p><arg>$PULSE_SERVER</arg>: the server string specifying the server to connect to when a client asks for a sound server connection and doesn't explicitly ask for a specific server.</p>
 432
 433     <p><arg>$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>
 434
 435     <p><arg>$PULSE_SOURCE</arg>: the symbolic name of the source to connect to when a client creates a record stream and doesn't explicitly ask for a specific source.</p>
 436
 437     <p><arg>$PULSE_BINARY</arg>: path of PulseAudio executable to run when server auto-spawning is used.</p>
 438
 439     <p><arg>$PULSE_CLIENTCONFIG</arg>: path of file that shall be read instead of <file>client.conf</file> (see above) for client configuration.</p>
 440
 441     <p>These environment settings take precedence -- if set -- over the configuration settings from <file>client.conf</file> (see above).</p>
 442
 443   </section>
 444
 445   <section name="Authors">
 446     <p>The PulseAudio Developers &lt;@PACKAGE_BUGREPORT@&gt;; PulseAudio is available from <url href="@PACKAGE_URL@"/></p>
 447   </section>
 448
 449   <section name="See also">
 450     <p>
 451       <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"/>
 452     </p>
 453   </section>
 454
 455 </manpage>