Provided by: acpid_2.0.26-1ubuntu2_i386 bug


       acpid - Advanced Configuration and Power Interface event daemon


       acpid [options]


       acpid  is designed to notify user-space programs of ACPI events.  acpid
       should be started during the system boot, and will run as a  background
       process,  by default.  It will open an events file (/proc/acpi/event by
       default) and attempt to read whole lines which represent  ACPI  events.
       If the events file does not exist, acpid will attempt to connect to the
       Linux kernel via the input layer and netlink.  When an  ACPI  event  is
       received from one of these sources, acpid will examine a list of rules,
       and execute the rules that match  the  event.  acpid  will  ignore  all
       incoming  ACPI  events  if  a  lock  file  exists  (/var/lock/acpid  by

       Rules are defined by simple configuration files.  acpid will look in  a
       configuration  directory  (/etc/acpi/events  by default), and parse all
       regular files with names that consist entirely of upper and lower  case
       letters,  digits,  underscores,  and hyphens (similar to run-parts(8)).
       Each file must define two things: an event and an  action.   Any  blank
       lines,  or lines where the first character is a hash ('#') are ignored.
       Extraneous lines are flagged as warnings, but are not fatal.  Each line
       has  three  tokens:  the key, a literal equal sign, and the value.  The
       key can be up to 63 characters, and is case-insensitive (but whitespace
       matters).   The  value  can  be  up  to 511 characters, and is case and
       whitespace sensitive.

       The event value is a regular expression (see regcomp(3)), against which
       events are matched.

       The  action  value  is a commandline, which will be invoked via /bin/sh
       whenever  an  event  matching  the  rule  in  question   occurs.    The
       commandline  may  include  shell-special  characters,  and they will be
       preserved.  The only special characters in  an  action  value  are  "%"
       escaped.   The  string "%e" will be replaced by the literal text of the
       event for which the  action  was  invoked.   This  string  may  contain
       spaces, so the commandline must take care to quote the "%e" if it wants
       a single token.  The string "%%" will be replaced  by  a  literal  "%".
       All other "%" escapes are reserved, and will cause a rule to not load.

       This  feature  allows  multiple  rules to be defined for the same event
       (though no ordering is guaranteed), as well as one rule to  be  defined
       for  multiple events.  To force acpid to reload the rule configuration,
       send it a SIGHUP.

       The pseudo-action <drop> causes the event to be dropped completely  and
       no  further  processing  undertaken;  clients  connecting  via the UNIX
       domain socket (see below) will not be notified of the event.  This  may
       be  useful  on  some  machines,  such as certain laptops which generate
       spurious battery events at frequent intervals. The name of this pseudo-
       action may be redefined with a commandline option.

       In  addition  to  rule  files, acpid also accepts connections on a UNIX
       domain socket (/var/run/acpid.socket by default).  Any application  may
       connect  to  this  socket.  Once connected, acpid will send the text of
       all ACPI events to the client.  The client has  the  responsibility  of
       filtering  for messages about which it cares.  acpid will not close the
       client socket except in the case of a SIGHUP or acpid exiting.

       For faster startup, this socket can be passed in as stdin so that acpid
       need  not  create the socket.  In addition, if a socket is passed in as
       stdin, acpid will not daemonize.  It will be run in  foreground.   This
       behavior is provided to support systemd(1).

       acpid  will log all of its activities, as well as the stdout and stderr
       of any actions, to syslog.

       All the default files and directories can be changed  with  commandline


       -c, --confdir directory
                   This  option changes the directory in which acpid looks for
                   rule configuration files.  Default is /etc/acpi/events.

       -C, --clientmax number
                   This option changes the maximum number of  non-root  socket
                   connections which can be made to the acpid socket.  Default
                   is 256.

       -d, --debug This option increases the acpid debug level by one.  If the
                   debug  level is non-zero, acpid will run in the foreground,
                   and will log to stderr, in addition to the regular syslog.

       -e, --eventfile filename
                   This option changes the event file from which  acpid  reads
                   events.  Default is /proc/acpi/event.

       -n, --netlink
                   This  option  forces  acpid  to  use the Linux kernel input
                   layer and netlink interface for ACPI events.

       -f, --foreground
                   This option keeps acpid in the foreground by not forking at

       -l, --logevents
                   This option tells acpid to log information about all events
                   and actions.

       -L, --lockfile filename
                   This option changes  the  lock  file  used  to  stop  event
                   processing.  Default is /var/lock/acpid.

       -g, --socketgroup groupname
                   This  option changes the group ownership of the UNIX domain
                   socket to which acpid publishes events.

       -m, --socketmode mode
                   This option changes the  permissions  of  the  UNIX  domain
                   socket to which acpid publishes events.  Default is 0666.

       -s, --socketfile filename
                   This  option  changes  the  name  of the UNIX domain socket
                   which acpid opens.  Default is /var/run/acpid.socket.

       -S, --nosocket filename
                   This option tells acpid not to open a UNIX  domain  socket.
                   This  overrides the -s option, and negates all other socket

       -p, --pidfile filename
                   This option tells acpid to use the specified  file  as  its
                   pidfile.   If the file exists, it will be removed and over-
                   written.  Default is /var/run/

       -r, --dropaction action
                   This option defines the pseudo-action which tells acpid  to
                   abort   all   processing  of  an  event,  including  client
                   notifications.  Default is <drop>.

       -t, --tpmutefix
                   This option enables special handling of the mute button for
                   certain ThinkPad models with mute LEDs that get out of sync
                   with the mute state when the  mute  button  is  held  down.
                   With  this  option,  the  mute  button  will  generate  the
                   following events in sync with the number of  presses  (and,
                   by extension, the state of the LED):

                   button/mute MUTE (key pressed) K
                   button/mute MUTE (key released) K

       -v, --version
                   Print version information and exit.

       -h, --help  Show help and exit.


       This example will shut down your system if you press the power button.

       Create a file named /etc/acpi/events/power that contains the following:

              action=/etc/acpi/ "%e"

       Then   create   a  file  named  /etc/acpi/  that  contains  the

              /sbin/shutdown -h now "Power button pressed"

       Now, when acpid is running, a press of the power button will cause  the
       rule    in    /etc/acpi/events/power   to   trigger   the   script   in
       /etc/acpi/  The script will then shut down the system.


       acpid is a simple program that runs scripts in response to ACPI  events
       from  the  kernel.   When  there's  trouble, the problem is rarely with
       acpid itself.  The following are some suggestions for finding the  most
       common sources of ACPI-related problems.

       When  troubleshooting  acpid,  it  is  important to be aware that other
       parts of a system might be handling ACPI events.  systemd(1) is capable
       of handling the power switch and various other events that are commonly
       handled  by  acpid.   See  the   description   of   HandlePowerKey   in
       logind.conf(5)  for  more.  Some window managers also take over acpid's
       normal handling of the power button and other events.

       kacpimon(8) can be used to verify that the  expected  ACPI  events  are
       coming  in.  See the man page for kacpimon(8) for the proper procedure.
       If the events aren't coming in, you've probably  got  a  kernel  driver

       If the expected events are coming in, then you'll need to check and see
       if your window manager is responsible for handling these events.   Some
       are,  some  aren't.   (E.g.  in  Ubuntu  14.04 (Unity/GNOME), there are
       settings for the laptop lid in the System Settings > Power > "When  the
       lid  is  closed"  fields.)   If  your window manager is responsible for
       handling the problematic event, and you've got it configured  properly,
       then you may have a window manager issue.

       Lastly,  take  a  look  in  /etc/acpi/events  (see  above).  Is there a
       configuration  file  in  there  for  the  event   in   question   (e.g.
       /etc/acpi/events/lidbtn  for  laptop  lid  open/close  events)?   Is it
       properly connected to a script (e.g. /etc/acpi/  Is that script
       working?   It's  not  unusual  for  an acpid script to check and see if
       there is a window manager running, then do nothing if there  is.   This
       means it is up to the window manager to handle this event.


       acpid should work on any linux kernel released since 2003.




       There  are  no  known  bugs.   To file bug reports, see PROJECT WEBSITE


       regcomp(3),  sh(1),   socket(2),   connect(2),   init(1),   systemd(1),
       acpi_listen(8), kacpimon(8)



       Ted Felix <>
       Tim Hockin <>
       Andrew Henroid