Provided by: pulseaudio_13.0-1ubuntu1_amd64 bug

NAME

       pulseaudio - The PulseAudio Sound System

SYNOPSIS

       pulseaudio [options]

       pulseaudio --help

       pulseaudio --version

       pulseaudio --dump-conf

       pulseaudio --dump-modules

       pulseaudio --dump-resample-methods

       pulseaudio --cleanup-shm

       pulseaudio --start

       pulseaudio --kill

       pulseaudio --check

DESCRIPTION

       PulseAudio is a networked low-latency sound server for Linux, POSIX and Windows systems.

OPTIONS

       -h | --help
              Show help.

       --version
              Show version information.

       --dump-conf
              Load  the  daemon  configuration  file  daemon.conf  (see  below),  parse remaining
              configuration  options  on  the  command  line  and  dump  the   resulting   daemon
              configuration, in a format that is compatible with daemon.conf.

       --dump-modules
              List available loadable modules. Combine with -v for a more elaborate listing.

       --dump-resample-methods
              List available audio resamplers.

       --cleanup-shm
              Identify  stale PulseAudio POSIX shared memory segments in /dev/shm and remove them
              if possible. This is done implicitly whenever a new daemon starts up  or  a  client
              tries  to  connect  to  a daemon. It should normally not be necessary to issue this
              command by hand. Only available  on  systems  with  POSIX  shared  memory  segments
              implemented via a virtual file system mounted to /dev/shm (e.g. Linux).

       --start
              Start  PulseAudio  if  it  is  not  running  yet.  This  is different from starting
              PulseAudio without --start which would fail if PA is already running. PulseAudio is
              guaranteed to be fully initialized when this call returns. Implies --daemonize.

       -k | --kill
              Kill  an  already  running  PulseAudio  daemon  of  the calling user (Equivalent to
              sending a SIGTERM).

       --check
              Return 0 as return code when the PulseAudio  daemon  is  already  running  for  the
              calling  user,  or non-zero otherwise. Produces no output on the console except for
              errors to stderr.

       --system[=BOOL]
              Run as system-wide instance instead of per-user. Please  note  that  this  disables
              certain  features  of PulseAudio and is generally not recommended unless the system
              knows no  local  users  (e.g.  is  a  thin  client).  This  feature  needs  special
              configuration and a dedicated UNIX user set up. It is highly recommended to combine
              this with --disallow-module-loading (see below).

       -D | --daemonize[=BOOL]
              Daemonize after startup, i.e. detach from the terminal. Note that when running as a
              systemd service you should use --daemonize=no for systemd notification to work.

       --fail[=BOOL]
              Fail  startup  when  any of the commands specified in the startup script default.pa
              (see below) fails.

       --high-priority[=BOOL]
              Try to acquire a high Unix nice level. This will only succeed if the  calling  user
              has  a  non-zero  RLIMIT_NICE resource limit set (on systems that support this), or
              we're called SUID root (see below), or we are configure to be run as system  daemon
              (see  --system  above).  It  is  recommended  to  enable  this,  since it is only a
              negligible security risk (see below).

       --realtime[=BOOL]
              Try to acquire a real-time scheduling for PulseAudio's I/O threads. This will  only
              succeed  if  the  calling  user has a non-zero RLIMIT_RTPRIO resource limit set (on
              systems that support this), or we're called  SUID  root  (see  below),  or  we  are
              configure  to  be  run  as system daemon (see --system above). It is recommended to
              enable this only for trusted users, since it is a major security risk (see below).

       --disallow-module-loading[=BOOL]
              Disallow module loading  after  startup.  This  is  a  security  feature  since  it
              disallows  additional  module  loading  during  runtime  and on user request. It is
              highly recommended when --system is used  (see  above).  Note  however,  that  this
              breaks certain features like automatic module loading on hot plug.

       --disallow-exit[=BOOL]
              Disallow user requested exit

       --exit-idle-time=SECS
              Terminate  the  daemon  after the last client quit and this time in seconds passed.
              Use a negative value to disable this feature. Defaults to 20.

              When PulseAudio runs in the per-user mode and detects a  login  session,  then  any
              positive  value will be reset to 0 so that PulseAudio will terminate immediately on
              logout. A positive value therefore has effect only in environments where there's no
              support  for  login session tracking. A negative value can still be used to disable
              any automatic exit.

              When PulseAudio runs in the system mode, automatic exit is always disabled, so this
              option does nothing.

       --scache-idle-time=SECS
              Unload  autoloaded  samples  from  the  cache  when  they haven't been used for the
              specified number of seconds.

       --log-level[=LEVEL]
              If an argument is passed, set the log  level  to  the  specified  value,  otherwise
              increase the configured verbosity level by one. The log levels are numerical from 0
              to 4, corresponding to error, warn, notice,  info,  debug.  Default  log  level  is
              notice,  i.e.  all  log  messages  with  lower log levels are printed: error, warn,
              notice.

       -v | --verbose
              Increase the configured verbosity level by one  (see  --log-level  above).  Specify
              multiple times to increase log level multiple times.

       --log-target={auto,syslog,journal,stderr,file:PATH,newfile:PATH}
              Specify  the  log  target.  If  set to auto (which is the default), then logging is
              directed to syslog when --daemonize is passed,  otherwise  to  STDERR.  If  set  to
              journal logging is directed to the systemd journal. If set to file:PATH, logging is
              directed to the file indicated by PATH.  newfile:PATH  is  otherwise  the  same  as
              file:PATH,  but existing files are never overwritten. If the specified file already
              exists, a suffix is added to the file name to avoid overwriting.

       --log-meta[=BOOL]
              Show source code location in log messages.

       --log-time[=BOOL]
              Show timestamps in log messages.

       --log-backtrace=FRAMES
              When FRAMES is greater than 0, log for each message a stack trace up to the  number
              of specified stack frames.

       -p | --dl-search-path=PATH
              Set the search path for dynamic shared objects (plugins).

       --resample-method=METHOD
              Use  the  specified  resampler  by  default  (See --dump-resample-methods above for
              possible values).

       --use-pid-file[=BOOL]
              Create a PID file. If this options is disabled it is possible to run multiple sound
              servers per user.

       --no-cpu-limit[=BOOL]
              Do  not  install  CPU  load  limiter  on  platforms  that  support  it. By default,
              PulseAudio will terminate itself when it notices that it  takes  up  too  much  CPU
              time.  This  is  useful  as  a  protection  against  system  lockups when real-time
              scheduling is used (see below). Disabling this mechanism is useful  when  debugging
              PulseAudio with tools like valgrind(1) which slow down execution.

       --disable-shm[=BOOL]
              PulseAudio clients and the server can exchange audio data via POSIX or memfd shared
              memory segments (on  systems  that  support  this).  If  disabled  PulseAudio  will
              communicate  exclusively  over  sockets.  Please note that data transfer via shared
              memory segments is always disabled when PulseAudio is running with --system enabled
              (see above).

       --enable-memfd[=BOOL]
              PulseAudio  clients  and  the  server  can  exchange  audio  data  via memfds - the
              anonymous Linux Kernel shared memory mechanism (on kernels that support  this).  If
              disabled PulseAudio will communicate via POSIX shared memory.

       -L | --load="MODULE ARGUMENTS"
              Load the specified plugin module with the specified arguments.

       -F | --file=FILENAME
              Run  the  specified  script  on startup. May be specified multiple times to specify
              multiple scripts to be run in order. Combine with -n  to  disable  loading  of  the
              default script default.pa (see below).

       -C     Open  a  command  interpreter  on  STDIN/STDOUT  after startup. This may be used to
              configure PulseAudio dynamically during runtime. Equivalent to --load=module-cli.

       -n     Don't load default script  file  default.pa  (see  below)  on  startup.  Useful  in
              conjunction with -C or --file.

FILES

       ~/.config/pulse/daemon.conf,   /etc/pulse/daemon.conf:   configuration  settings  for  the
       PulseAudio daemon. If the version in the user's home directory does not exist  the  global
       configuration file is loaded. See pulse-daemon.conf(5) for more information.

       ~/.config/pulse/default.pa,  /etc/pulse/default.pa:  the  default  configuration script to
       execute when the PulseAudio daemon is started. If the version in the user's home directory
       does  not  exist  the  global  configuration  script is loaded. See default.pa(5) for more
       information.

       ~/.config/pulse/client.conf, /etc/pulse/client.conf: configuration settings for PulseAudio
       client applications. If the version in the user's home directory does not exist the global
       configuration file is loaded. See pulse-client.conf(5) for more information.

SIGNALS

       SIGINT, SIGTERM: the PulseAudio daemon will shut down (Same as --kill).

       SIGHUP: dump a long status report to STDOUT or syslog, depending on the configuration.

       SIGUSR1: load module-cli, allowing runtime reconfiguration via STDIN/STDOUT.

       SIGUSR2: load module-cli-protocol-unix, allowing runtime  reconfiguration  via  a  AF_UNIX
       socket. See pacmd(1) for more information.

UNIX GROUPS AND USERS

       Group  pulse-rt:  if  the  PulseAudio  binary  is marked SUID root, then membership of the
       calling user in this group decides whether real-time and/or  high-priority  scheduling  is
       enabled. Please note that enabling real-time scheduling is a security risk (see below).

       Group  pulse-access:  if  PulseAudio  is  running  as a system daemon (see --system above)
       access is granted to members of this group when  they  connect  via  AF_UNIX  sockets.  If
       PulseAudio is running as a user daemon this group has no meaning.

       User  pulse, group pulse: if PulseAudio is running as a system daemon (see --system above)
       and is started as root the daemon will drop privileges and become a  normal  user  process
       using  this  user and group. If PulseAudio is running as a user daemon this user and group
       has no meaning.

REAL-TIME AND HIGH-PRIORITY SCHEDULING

       To minimize the risk of drop-outs during playback it is recommended to run PulseAudio with
       real-time scheduling if the underlying platform supports it. This decouples the scheduling
       latency of the PulseAudio daemon from the system load and is thus the  best  way  to  make
       sure that PulseAudio always gets CPU time when it needs it to refill the hardware playback
       buffers. Unfortunately this is a security risk on most systems, since PulseAudio  runs  as
       user  process,  and  giving  realtime scheduling privileges to a user process always comes
       with the risk that the user misuses it to lock up the system -- which  is  possible  since
       making a process real-time effectively disables preemption.

       To  minimize  the  risk  PulseAudio by default does not enable real-time scheduling. It is
       however recommended to enable it on trusted systems. To  do  that  start  PulseAudio  with
       --realtime  (see  above) or enabled the appropriate option in daemon.conf. Since acquiring
       realtime scheduling is a privileged operation on most systems, some special changes to the
       system  configuration  need  to be made to allow them to the calling user. Two options are
       available:

       On newer Linux systems the system resource limit RLIMIT_RTPRIO (see setrlimit(2) for  more
       information) can be used to allow specific users to acquire real-time scheduling. This can
       be configured in /etc/security/limits.conf, a resource limit of 9 is recommended.

       Alternatively, the SUID root bit can be set for the PulseAudio binary.  Then,  the  daemon
       will  drop  root privileges immediately on startup, however retain the CAP_NICE capability
       (on systems that support it), but only if the calling user is a  member  of  the  pulse-rt
       group  (see  above).  For  all  other  users all capabilities are dropped immediately. The
       advantage of this solution is that the  real-time  privileges  are  only  granted  to  the
       PulseAudio daemon -- not to all the user's processes.

       Alternatively, if the risk of locking up the machine is considered too big to enable real-
       time scheduling, high-priority scheduling can  be  enabled  instead  (i.e.  negative  nice
       level).  This  can  be  enabled  by  passing  --high-priority  (see  above)  when starting
       PulseAudio and may also be enabled with the appropriate option  in  daemon.conf.  Negative
       nice  levels  can  only  be enabled when the appropriate resource limit RLIMIT_NICE is set
       (see setrlimit(2) for more information), possibly configured in /etc/security/limits.conf.
       A resource limit of 31 (corresponding with nice level -11) is recommended.

ENVIRONMENT VARIABLES

       The  PulseAudio  client  libraries  check  for  the existence of the following environment
       variables and change their local configuration accordingly:

       $PULSE_SERVER: 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. The server
       string is a list of server addresses separated by whitespace which are tried  in  turn.  A
       server address consists of an optional address type specifier (unix:, tcp:, tcp4:, tcp6:),
       followed by a path or host address. A host address may include an optional port number.  A
       server  address  may  be  prefixed  by a string enclosed in {}. In this case the following
       server address is ignored unless the prefix  string  equals  the  local  hostname  or  the
       machine id (/etc/machine-id).

       $PULSE_SINK:  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.

       $PULSE_SOURCE: 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.

       $PULSE_BINARY: path of PulseAudio executable to run when server auto-spawning is used.

       $PULSE_CLIENTCONFIG:  path  of  file that shall be read instead of client.conf (see above)
       for client configuration.

       $PULSE_COOKIE: path of file that contains the PulseAudio authentication  cookie.  Defaults
       to ~/.config/pulse/cookie.

       These  environment  settings  take precedence -- if set -- over the configuration settings
       from client.conf (see above).

AUTHORS

       The PulseAudio Developers <pulseaudio-discuss (at) lists  (dot)  freedesktop  (dot)  org>;
       PulseAudio is available from http://pulseaudio.org/

SEE ALSO

       pulse-daemon.conf(5), default.pa(5), pulse-client.conf(5), pacmd(1)