code.delx.au - pulseaudio/blob - man/pulseaudio.1.xml.in

   1 <?xml version="1.0"?><!--*-nxml-*-->
   2 <!DOCTYPE manpage SYSTEM "xmltoman.dtd">
   3 <?xml-stylesheet type="text/xsl" href="xmltoman.xsl" ?>
   4
   5 <!--
   6 This file is part of PulseAudio.
   7
   8 PulseAudio is free software; you can redistribute it and/or modify it
   9 under the terms of the GNU Lesser General Public License as
  10 published by the Free Software Foundation; either version 2.1 of the
  11 License, or (at your option) any later version.
  12
  13 PulseAudio is distributed in the hope that it will be useful, but WITHOUT
  14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
  16 Public License for more details.
  17
  18 You should have received a copy of the GNU Lesser General Public
  19 License along with PulseAudio; if not, write to the Free Software
  20 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21 USA.
  22 -->
  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,newfile: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. <arg>newfile:PATH</arg> is otherwise
 227       the same as file:PATH, but existing files are never overwritten.
 228       If the specified file already exists, a suffix is added to the
 229       file name to avoid overwriting.</p></optdesc>
 230     </option>
 231
 232     <option>
 233       <p><opt>--log-meta</opt><arg>[=BOOL]</arg></p>
 234
 235       <optdesc><p>Show source code location in log messages.</p></optdesc>
 236     </option>
 237
 238     <option>
 239       <p><opt>--log-time</opt><arg>[=BOOL]</arg></p>
 240
 241       <optdesc><p>Show timestamps in log messages.</p></optdesc>
 242     </option>
 243
 244     <option>
 245       <p><opt>--log-backtrace</opt><arg>=FRAMES</arg></p>
 246
 247       <optdesc><p>When FRAMES is greater than 0, log for each message a
 248       stack trace up to the number of specified stack frames.</p></optdesc>
 249     </option>
 250
 251     <option>
 252       <p><opt>--p | --dl-search-path</opt><arg>=PATH</arg></p>
 253
 254       <optdesc><p>Set the search path for dynamic shared objects
 255       (plugins).</p></optdesc>
 256     </option>
 257
 258     <option>
 259       <p><opt>--resample-method</opt><arg>=METHOD</arg></p>
 260
 261       <optdesc><p>Use the specified resampler by default (See
 262       <opt>--dump-resample-methods</opt> above for possible
 263       values).</p></optdesc>
 264     </option>
 265
 266     <option>
 267       <p><opt>--use-pid-file</opt><arg>[=BOOL]</arg></p>
 268
 269       <optdesc><p>Create a PID file. If this options is disabled it is possible to run multiple sound servers per user.</p></optdesc>
 270     </option>
 271
 272     <option>
 273       <p><opt>--no-cpu-limit</opt><arg>[=BOOL]</arg></p>
 274
 275       <optdesc><p>Do not install CPU load limiter on platforms that
 276       support it. By default, PulseAudio will terminate itself when it
 277       notices that it takes up too much CPU time. This is useful as a
 278       protection against system lockups when real-time scheduling is
 279       used (see below). Disabling this mechanism is useful when
 280       debugging PulseAudio with tools like <manref name="valgrind"
 281       section="1"/> which slow down execution.</p></optdesc>
 282     </option>
 283
 284     <option>
 285       <p><opt>--disable-shm</opt><arg>[=BOOL]</arg></p>
 286
 287       <optdesc><p>PulseAudio clients and the server can exchange audio
 288       data via POSIX shared memory segments (on systems that support
 289       this). If disabled PulseAudio will communicate exclusively over
 290       sockets. Please note that data transfer via shared memory
 291       segments is always disabled when PulseAudio is running with
 292       <opt>--system</opt> enabled (see above).</p></optdesc>
 293     </option>
 294
 295     <option>
 296       <p><opt>-L | --load</opt><arg>="MODULE ARGUMENTS"</arg></p>
 297
 298       <optdesc><p>Load the specified plugin module with the specified
 299       arguments.</p></optdesc>
 300     </option>
 301
 302     <option>
 303       <p><opt>-F | --file</opt><arg>=FILENAME</arg></p>
 304
 305       <optdesc><p>Run the specified script on startup. May be
 306       specified multiple times to specify multiple scripts to be run
 307       in order. Combine with <opt>-n</opt> to disable loading of the
 308       default script <file>default.pa</file> (see below).</p></optdesc>
 309     </option>
 310     <option>
 311       <p><opt>-C</opt></p>
 312
 313       <optdesc><p>Open a command interpreter on STDIN/STDOUT after
 314       startup. This may be used to configure PulseAudio dynamically
 315       during runtime. Equivalent to
 316       <opt>--load</opt><arg>=module-cli</arg>.</p></optdesc>
 317     </option>
 318     <option>
 319       <p><opt>-n</opt></p>
 320
 321       <optdesc><p>Don't load default script file
 322       <file>default.pa</file> (see below) on startup. Useful in
 323       conjunction with <opt>-C</opt> or
 324       <opt>--file</opt>.</p></optdesc>
 325     </option>
 326
 327
 328   </options>
 329
 330   <section name="Files">
 331
 332     <p><file>~/.config/pulse/daemon.conf</file>,
 333     <file>@PA_DEFAULT_CONFIG_DIR@/daemon.conf</file>: configuration settings
 334     for the PulseAudio daemon. If the version in the user's home
 335     directory does not exist the global configuration file is
 336     loaded. See <manref name="pulse-daemon.conf" section="5"/> for
 337     more information.</p>
 338
 339     <p><file>~/.config/pulse/default.pa</file>,
 340     <file>@PA_DEFAULT_CONFIG_DIR@/default.pa</file>: the default configuration
 341     script to execute when the PulseAudio daemon is started. If the
 342     version in the user's home directory does not exist the global
 343     configuration script is loaded. See <manref name="default.pa"
 344     section="5"/> for more information.</p>
 345
 346     <p><file>~/.config/pulse/client.conf</file>,
 347     <file>@PA_DEFAULT_CONFIG_DIR@/client.conf</file>: configuration settings
 348     for PulseAudio client applications. If the version in the user's
 349     home directory does not exist the global configuration file is
 350     loaded.  See <manref name="pulse-client.conf" section="5"/> for
 351     more information.</p>
 352
 353   </section>
 354
 355   <section name="Signals">
 356
 357     <p><arg>SIGINT, SIGTERM</arg>: the PulseAudio daemon will shut
 358     down (Same as <opt>--kill</opt>).</p>
 359
 360     <p><arg>SIGHUP</arg>: dump a long status report to STDOUT or
 361     syslog, depending on the configuration.</p>
 362
 363     <p><arg>SIGUSR1</arg>: load module-cli, allowing runtime
 364     reconfiguration via STDIN/STDOUT.</p>
 365
 366     <p><arg>SIGUSR2</arg>: load module-cli-protocol-unix, allowing
 367     runtime reconfiguration via a AF_UNIX socket. See <manref
 368     name="pacmd" section="1"/> for more information.</p>
 369
 370   </section>
 371
 372   <section name="UNIX Groups and users">
 373
 374     <p>Group <arg>pulse-rt</arg>: if the PulseAudio binary is marked
 375     SUID root, then membership of the calling user in this group
 376     decides whether real-time and/or high-priority scheduling is
 377     enabled. Please note that enabling real-time scheduling is a
 378     security risk (see below).</p>
 379
 380     <p>Group <arg>pulse-access</arg>: if PulseAudio is running as a system
 381     daemon (see <opt>--system</opt> above) access is granted to
 382     members of this group when they connect via AF_UNIX sockets. If
 383     PulseAudio is running as a user daemon this group has no
 384     meaning.</p>
 385
 386     <p>User <arg>pulse</arg>, group <arg>pulse</arg>: if PulseAudio is running as a system
 387     daemon (see <opt>--system</opt> above) and is started as root the
 388     daemon will drop privileges and become a normal user process using
 389     this user and group. If PulseAudio is running as a user daemon
 390     this user and group has no meaning.</p>
 391   </section>
 392
 393   <section name="Real-time and high-priority scheduling">
 394     <p>To minimize the risk of drop-outs during playback it is
 395     recommended to run PulseAudio with real-time scheduling if the
 396     underlying platform supports it. This decouples the scheduling
 397     latency of the PulseAudio daemon from the system load and is thus
 398     the best way to make sure that PulseAudio always gets CPU time
 399     when it needs it to refill the hardware playback
 400     buffers. Unfortunately this is a security risk on most systems,
 401     since PulseAudio runs as user process, and giving realtime
 402     scheduling privileges to a user process always comes with the risk
 403     that the user misuses it to lock up the system -- which is
 404     possible since making a process real-time effectively disables
 405     preemption.</p>
 406
 407     <p>To minimize the risk PulseAudio by default does not enable
 408     real-time scheduling. It is however recommended to enable it
 409     on trusted systems. To do that start PulseAudio with
 410     <opt>--realtime</opt> (see above) or enabled the appropriate option in
 411     <file>daemon.conf</file>. Since acquiring realtime scheduling is a
 412     privileged operation on most systems, some special changes to the
 413     system configuration need to be made to allow them to the calling
 414     user. Two options are available:</p>
 415
 416     <p>On newer Linux systems the system resource limit RLIMIT_RTPRIO
 417     (see <manref name="setrlimit" section="2"/> for more information)
 418     can be used to allow specific users to acquire real-time
 419     scheduling. This can be configured in
 420     <file>/etc/security/limits.conf</file>, a resource limit of 9 is recommended.</p>
 421
 422     <p>Alternatively, the SUID root bit can be set for the PulseAudio
 423     binary. Then, the daemon will drop root privileges immediately on
 424     startup, however retain the CAP_NICE capability (on systems that
 425     support it), but only if the calling user is a member of the
 426     <arg>pulse-rt</arg> group (see above). For all other users all
 427     capabilities are dropped immediately. The advantage of this
 428     solution is that the real-time privileges are only granted to the
 429     PulseAudio daemon -- not to all the user's processes.</p>
 430
 431     <p>Alternatively, if the risk of locking up the machine is
 432     considered too big to enable real-time scheduling, high-priority
 433     scheduling can be enabled instead (i.e. negative nice level). This
 434     can be enabled by passing <opt>--high-priority</opt> (see above)
 435     when starting PulseAudio and may also be enabled with the
 436     appropriate option in <file>daemon.conf</file>. Negative nice
 437     levels can only be enabled when the appropriate resource limit
 438     RLIMIT_NICE is set (see <manref name="setrlimit" section="2"/> for
 439     more information), possibly configured in
 440     <file>/etc/security/limits.conf</file>. A resource limit of 31
 441     (corresponding with nice level -11) is recommended.</p>
 442   </section>
 443
 444   <section name="Environment variables">
 445
 446     <p>The PulseAudio client libraries check for the existence of the
 447     following environment variables and change their local configuration accordingly:</p>
 448
 449     <p><arg>$PULSE_SERVER</arg>: the server string specifying the server to connect to when a client asks for a sound server connection and doesn't explicitly ask for a specific server.</p>
 450
 451     <p><arg>$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>
 452
 453     <p><arg>$PULSE_SOURCE</arg>: the symbolic name of the source to connect to when a client creates a record stream and doesn't explicitly ask for a specific source.</p>
 454
 455     <p><arg>$PULSE_BINARY</arg>: path of PulseAudio executable to run when server auto-spawning is used.</p>
 456
 457     <p><arg>$PULSE_CLIENTCONFIG</arg>: path of file that shall be read instead of <file>client.conf</file> (see above) for client configuration.</p>
 458
 459     <p><arg>$PULSE_COOKIE</arg>: path of file that contains the PulseAudio
 460     authentication cookie. Defaults to <file>~/.config/pulse/cookie</file>.</p>
 461
 462     <p>These environment settings take precedence -- if set -- over the configuration settings from <file>client.conf</file> (see above).</p>
 463
 464   </section>
 465
 466   <section name="Authors">
 467     <p>The PulseAudio Developers &lt;@PACKAGE_BUGREPORT@&gt;; PulseAudio is available from <url href="@PACKAGE_URL@"/></p>
 468   </section>
 469
 470   <section name="See also">
 471     <p>
 472       <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"/>
 473     </p>
 474   </section>
 475
 476 </manpage>