* System Monitor Plugins

  This is the description of the system monitor plugins available in
  xmobar. Some of them are only installed when an optional build
  option is set: we mention that fact, when needed, in their
  description.

  Each monitor has an =alias= to be used in the output
  template. Monitors may have default aliases, see the documentation
  of the monitor in question.

  There are two types of arguments: ones that all monitors share (the
  so called /default monitor arguments/) and arguments that are specific
  to a certain monitor.

  All Monitors accept a common set of arguments, described below in
  [[Default Monitor Arguments]]. Some monitors also accept additional
  options that are specific to them. When specifying the list of
  arguments in your configuration, the common options come first,
  followed by =--=, followed by any monitor-specific options. For
  example, the following [[=Battery Args RefreshRate=][Battery]] configuration first sets the global
  =template= and =Low= arguments and then specifies the battery-specific
  =off= option.

  #+begin_src haskell
    Run Battery
      [ "--template", "<acstatus>"
      , "--Low"     , "15"
      -- battery specific options start here.
      , "--"
      , "--off"     , "<left> (<timeleft>)"
      ]
      100
  #+end_src

** Icon Patterns

Some monitors allow usage of strings that depend on some integer value
from 0 to 8 by replacing all occurrences of =%%= with it
(i.e. =<icon=/path/to/icon_%%.xpm/>= will be interpreted as
=<icon=/path/to/icon_3.xpm/>= when the value is =3=, also =%= is
interpreted as =%=, =%%= as =3=, =%%%= as =3%=, =%%%%= as =33= and so
on). Essentially it allows to replace vertical bars with custom
icons. For example,

#+begin_src haskell
  Run Brightness
    [ "-t", "<ipat>"
    , "--"
    , "--brightness-icon-pattern", "<icon=bright_%%.xpm/>"
    ] 30
#+end_src

Will display =bright_0.xpm= to =bright_8.xpm= depending on current
brightness value.

** Default Monitor Arguments

These are the options available for all monitors:

- =-t= /string/ Output template

  - Template for the monitor output. Field names must be enclosed
    between pointy brackets (=<foo>=) and will be substituted by the
    computed values. You can also specify the foreground (and
    optionally, background) color for a region by bracketing it between
    =<fc=fgcolor>= (or =<fc=fgcolor,bgcolor>=) and =</fc>=. The rest of
    the template is output verbatim.
  - Long option: =--template=
  - Default value: per monitor (see above).

- =-H= /number/ The high threshold.

  - Numerical values higher than /number/ will be displayed with the
    color specified by =-h= (see below).
  - Long option: =--High=
  - Default value: 66

- =-L= /number/ The low threshold.

  - Numerical values higher than /number/ and lower than the high
    threshold will be displayed with the color specified by =-n= (see
    below). Values lower than /number/ will use the =-l= color.
  - Long option: =--Low=
  - Default value: 33

- =-h= /color/ High threshold color.

  - Color for displaying values above the high threshold. /color/ can be
    either a name (e.g. "blue") or an hexadecimal RGB (e.g. "#FF0000").
  - Long option: =--high=
  - Default: none (use the default foreground).

- =-n= /color/ Color for 'normal' values

  - Color used for values greater than the low threshold but lower than
    the high one.
  - Long option: =--normal=
  - Default: none (use the default foreground).

- =-l= /color/ The low threshold color

  - Color for displaying values below the low threshold.
  - Long option: =--low=
  - Default: none (use the default foreground).

- =-S= /boolean/ Display optional suffixes

  - When set to a true designator ("True", "Yes" or "On"), optional
    value suffixes such as the '%' symbol or optional units will be
    displayed.
  - Long option: =--suffix=
  - Default: False.

- =-p= /number/ Percentages padding

  - Width, in number of digits, for quantities representing percentages.
    For instance =-p 3= means that all percentages in the monitor will
    be represented using 3 digits.
  - Long option: =--ppad=
  - Default value: 0 (don't pad)

- =-d= /number/ Decimal digits

  - Number of digits after the decimal period to use in float values.
  - Long option: =--ddigits=
  - Default value: 0 (display only integer part)

- =-m= /number/ Minimum field width

  - Minimum width, in number of characters, of the fields in the monitor
    template. Values whose printed representation is shorter than this
    value will be padded using the padding characters given by the =-c=
    option with the alignment specified by =-a= (see below).
  - Long option: =--minwidth=
  - Default: 0

- =-M= /number/ Maximum field width

  - Maximum width, in number of characters, of the fields in the monitor
    template. Values whose printed representation is longer than this
    value will be truncated.
  - Long option: =--maxwidth=
  - Default: 0 (no maximum width)

- =-e= /string/ Maximum width ellipsis

  - Ellipsis to be added to the field when it has reached its max width.
  - Long option: =--maxwidthellipsis=
  - Default: "" (no ellipsis)

- =-w= /number/ Fixed field width

  - All fields will be set to this width, padding or truncating as
    needed.
  - Long option: =--width=
  - Default: 0 (variable width)

- =-T= /number/ Maximum total width

  - Maximum total width of the text.
  - Long option: =--maxtwidth=
  - Default: 0 (no limit)

- =-E= /string/ Maximum total width ellipsis

  - Ellipsis to be added to the total text when it has reached its max
    width.
  - Long option: =--maxtwidthellipsis=
  - Default: "" (no ellipsis)

- =-c= /string/

  - Characters used for padding. The characters of /string/ are used
    cyclically. E.g., with =-P +- -w 6=, a field with value "foo" will
    be represented as "+-+foo".
  - Long option: =--padchars=
  - Default value: " "

- =-a= r|l Field alignment

  - Whether to use right (r) or left (l) alignment of field values when
    padding.
  - Long option: =--align=
  - Default value: r (padding to the left)

- =-b= /string/ Bar background

  - Characters used, cyclically, to draw the background of bars. For
    instance, if you set this option to "·.", an empty bar will look
    like this: =·.·.·.·.·.=
  - Long option: =--bback=
  - Default value: ":"

- =-f= /string/ Bar foreground

  - Characters used, cyclically, to draw the foreground of bars.
  - Long option: =--bfore=
  - Default value: "#"

- =-W= /number/ Bar width

  - Total number of characters used to draw bars.
  - Long option: =--bwidth=
  - Default value: 10
  - Special value: 0. When this parameter is 0, the percentage to
    display is interpreted as a position in the bar foreground string
    (given by =-f=), and the character at that position is displayed.

- =-x= /string/ N/A string

  - String to be used when the monitor is not available
  - Long option: =--nastring=
  - Default value: "N/A"

Commands' arguments must be set as a list. E.g.:

#+begin_src haskell
  Run Weather "EGPF" ["-t", "<station>: <tempC>C"] 36000
#+end_src

In this case xmobar will run the weather monitor, getting information
for the weather station ID EGPF (Glasgow Airport, as a homage to GHC)
every hour (36000 tenth of seconds), with a template that will output
something like:

#+begin_src shell
  Glasgow Airport: 16.0C
#+end_src

** Battery Monitors
*** =Battery Args RefreshRate=

 Same as

 #+begin_src haskell
   BatteryP ["BAT", "BAT0", "BAT1", "BAT2"] Args RefreshRate
 #+end_src

*** =BatteryP Dirs Args RefreshRate=

 - Aliases to =battery=

 - Dirs: list of directories in =/sys/class/power_supply/= where to look
   for the ACPI files of each battery. Example: =["BAT0","BAT1","BAT2"]=.
   Only up to 3 existing directories will be searched.

 - Args: default monitor arguments, plus the following specific ones
   (these options, being specific to the monitor, are to be specified
   after a =--= in the argument list):

   - =-O=: string for AC "on" status (default: "On")
   - =-i=: string for AC "idle" status (default: "On")
   - =-o=: string for AC "off" status (default: "Off")
   - =-L=: low power (=watts=) threshold (default: 10)
   - =-H=: high power threshold (default: 12)
   - =-l=: color to display power lower than the =-L= threshold
   - =-m=: color to display power lower than the =-H= threshold
   - =-h=: color to display power higher than the =-H= threshold
   - =-p=: color to display positive power (battery charging)
   - =-f=: file in =/sys/class/power_supply= with AC info (default:
     "AC/online")
   - =-A=: a number between 0 and 100, threshold below which the action
     given by =-a=, if any, is performed (default: 5)
   - =-a=: a string with a system command that is run when the percentage
     left in the battery is less or equal than the threshold given by the
     =-A= option. If not present, no action is undertaken.
   - =-P=: to include a percentage symbol in =left=.
   - =--on-icon-pattern=: dynamic string for current battery charge when
     AC is "on" in =leftipat=.
   - =--off-icon-pattern=: dynamic string for current battery charge when
     AC is "off" in =leftipat=.
   - =--idle-icon-pattern=: dynamic string for current battery charge
     when AC is "idle" in =leftipat=.
   - =--lows=: string for AC "off" status and power lower than the =-L=
     threshold (default: "")
   - =--mediums=: string for AC "off" status and power lower than the
     =-H= threshold (default: "")
   - =--highs=: string for AC "off" status and power higher than the =-H=
     threshold (default: "")

 - Variables that can be used with the =-t/--template= argument:
   =left=, =leftbar=, =leftvbar=, =leftipat=, =timeleft=, =watts=,
   =acstatus=

 - Default template: =Batt: <watts>, <left>% / <timeleft>=

 - Example (note that you need "--" to separate regular monitor options
   from Battery's specific ones):

   #+begin_src haskell
     Run BatteryP ["BAT0"]
                  ["-t", "<acstatus><watts> (<left>%)",
                   "-L", "10", "-H", "80", "-p", "3",
                   "--", "-O", "<fc=green>On</fc> - ", "-i", "",
                   "-L", "-15", "-H", "-5",
                   "-l", "red", "-m", "blue", "-h", "green",
                   "-a", "notify-send -u critical 'Battery running out!!'",
                   "-A", "3"]
                  600
   #+end_src

   In the above example, the thresholds before the =--= separator affect
   only the =<left>= and =<leftbar>= fields, while those after the
   separator affect how =<watts>= is displayed. For this monitor, neither
   the generic nor the specific options have any effect on =<timeleft>=.
   We are also telling the monitor to execute the unix command
   =notify-send= when the percentage left in the battery reaches 6%.

   It is also possible to specify template variables in the =-O= and =-o=
   switches, as in the following example:

   #+begin_src haskell
     Run BatteryP ["BAT0"]
                  ["-t", "<acstatus>"
                  , "-L", "10", "-H", "80"
                  , "-l", "red", "-h", "green"
                  , "--", "-O", "Charging", "-o", "Battery: <left>%"
                  ] 10
   #+end_src

 - The "idle" AC state is selected whenever the AC power entering the
   battery is zero.

*** =BatteryN Dirs Args RefreshRate Alias=

 Works like =BatteryP=, but lets you specify an alias for the monitor
 other than "battery". Useful in case you one separate monitors for more
 than one battery.
** Cpu and Memory Monitors
*** =Cpu Args RefreshRate=

 - Aliases to =cpu=
 - Args: default monitor arguments, plus:

   - =--load-icon-pattern=: dynamic string for cpu load in =ipat=

 - Thresholds refer to percentage of CPU load
 - Variables that can be used with the =-t/--template= argument:
   =total=, =bar=, =vbar=, =ipat=, =user=, =nice=, =system=, =idle=,
   =iowait=
 - Default template: =Cpu: <total>%=

*** =MultiCpu Args RefreshRate=

 - Aliases to =multicpu=
 - Args: default monitor arguments, plus:

   - =--load-icon-pattern=: dynamic string for overall cpu load in
     =ipat=.
   - =--load-icon-patterns=: dynamic string for each cpu load in
     =autoipat=, =ipat{i}=. This option can be specified several times.
     nth option corresponds to nth cpu.
   - =--fallback-icon-pattern=: dynamic string used by =autoipat= and
     =ipat{i}= when no =--load-icon-patterns= has been provided for
     =cpu{i}=
   - =--contiguous-icons=: flag (no value needs to be provided) that
     causes the load icons to be drawn without padding.

 - Thresholds refer to percentage of CPU load
 - Variables that can be used with the =-t/--template= argument:
   =autototal=, =autobar=, =autovbar=, =autoipat=, =autouser=,
   =autonice=, =autosystem=, =autoidle=, =total=, =bar=, =vbar=, =ipat=,
   =user=, =nice=, =system=, =idle=, =total0=, =bar0=, =vbar0=, =ipat0=,
   =user0=, =nice0=, =system0=, =idle0=, ... The auto* variables
   automatically detect the number of CPUs on the system and display one
   entry for each.
 - Default template: =Cpu: <total>%=

*** =CpuFreq Args RefreshRate=

 - Aliases to =cpufreq=

 - Args: default monitor arguments

 - Thresholds refer to frequency in GHz

 - Variables that can be used with the =-t/--template= argument:
   =cpu0=, =cpu1=, .., =cpuN=

 - Default template: =Freq: <cpu0>GHz=

 - This monitor requires acpi_cpufreq module to be loaded in kernel

 - Example:

   #+begin_src haskell
     Run CpuFreq ["-t", "Freq:<cpu0>|<cpu1>GHz", "-L", "0", "-H", "2",
                  "-l", "lightblue", "-n","white", "-h", "red"] 50
   #+end_src

*** =CoreTemp Args RefreshRate=

 - Aliases to =coretemp=

 - Args: default monitor arguments

 - Thresholds refer to temperature in degrees

 - Variables that can be used with the =-t/--template= argument:
   =core0=, =core1=, .., =coreN=

 - Default template: =Temp: <core0>C=

 - This monitor requires coretemp module to be loaded in kernel

 - Example:

   #+begin_src haskell
     Run CoreTemp ["-t", "Temp:<core0>|<core1>C",
                   "-L", "40", "-H", "60",
                   "-l", "lightblue", "-n", "gray90", "-h", "red"] 50
   #+end_src

*** =MultiCoreTemp Args RefreshRate=

 - Aliases to =multicoretemp=

 - Args: default monitor arguments, plus:

   - =--max-icon-pattern=: dynamic string for overall cpu load in
     =maxipat=.
   - =--avg-icon-pattern=: dynamic string for overall cpu load in
     =avgipat=.
   - =--mintemp=: temperature in degree Celsius, that sets the lower
     limit for percentage calculation.
   - =--maxtemp=: temperature in degree Celsius, that sets the upper
     limit for percentage calculation.
   - =--hwmon-path=: this monitor tries to find coretemp devices by
     looking for them in directories following the pattern
     =/sys/bus/platform/devices/coretemp.*/hwmon/hwmon*=, but some
     processors (notably Ryzen) might expose those files in a different
     tree (e.g., Ryzen) puts them somewhere in "/sys/class/hwmon/hwmon*",
     and the lookup is most costly. With this option, it is possible to
     explicitly specify the full path to the directory where the
     =tempN_label= and =tempN_input= files are located.

 - Thresholds refer to temperature in degree Celsius

 - Variables that can be used with the =-t/--template= argument: =max=,
   =maxpc=, =maxbar=, =maxvbar=, =maxipat=, =avg=, =avgpc=, =avgbar=,
   =avgvbar=, =avgipat=, =core0=, =core1=, ..., =coreN=

   The /pc, /bar, /vbar and /ipat variables are showing percentages on
   the scale defined by =--mintemp= and =--maxtemp=. The max* and avg*
   variables to the highest and the average core temperature.

 - Default template: =Temp: <max>°C - <maxpc>%=

 - This monitor requires coretemp module to be loaded in kernel

 - Example:

   #+begin_src haskell
     Run MultiCoreTemp ["-t", "Temp: <avg>°C | <avgpc>%",
                        "-L", "60", "-H", "80",
                        "-l", "green", "-n", "yellow", "-h", "red",
                        "--", "--mintemp", "20", "--maxtemp", "100"] 50
   #+end_src

*** =K10Temp Slot Args RefreshRate=

 - Aliases to =k10temp=

 - Slot: The PCI slot address of the k10temp device as a string.  You
   can find it as a subdirectory in =/sys/bus/pci/drivers/k10temp/=.

 - Args: default monitor arguments

 - Thresholds refer to temperature in degrees

 - Variables that can be used with the =-t/--template= argument:
   =Tctl=, =Tdie=, =Tccd1=, .., =Tccd8=

 - Default template: =Temp: <Tdie>C=

 - This monitor requires k10temp module to be loaded in kernel

 - It is important to note that not all measurements are available
   on on all models of processor. Of particular importance - Tdie
   (used in the default template) may not be present on processors
   prior to Zen (17h). Tctl, however, may be offset from the real
   temperature and so is not used by default.

 - Example:

   #+begin_src haskell
     Run K10Temp "0000:00:18.3"
                 ["-t", "Temp: <Tdie>C|<Tccd1>C",
                  "-L", "40", "-H", "60",
                  "-l", "lightblue", "-n", "gray90", "-h", "red"]
                 50
   #+end_src


*** =Memory Args RefreshRate=

 - Aliases to =memory=
 - Args: default monitor arguments, plus:

   - =--used-icon-pattern=: dynamic string for used memory ratio in
     =usedipat=.
   - =--free-icon-pattern=: dynamic string for free memory ratio in
     =freeipat=.
   - =--available-icon-pattern=: dynamic string for available memory
     ratio in =availableipat=.

 - Thresholds refer to percentage of used memory
 - Variables that can be used with the =-t/--template= argument:
   =total=, =free=, =buffer=, =cache=, =available=, =used=, =usedratio=,
   =usedbar=, =usedvbar=, =usedipat=, =freeratio=, =freebar=, =freevbar=,
   =freeipat=, =availableratio=, =availablebar=, =availablevbar=,
   =availableipat=
 - Default template: =Mem: <usedratio>% (<cache>M)=

*** =Swap Args RefreshRate=

 - Aliases to =swap=
 - Args: default monitor arguments
 - Thresholds refer to percentage of used swap
 - Variables that can be used with the =-t/--template= argument:
   =total=, =used=, =free=, =usedratio=
 - Default template: =Swap: <usedratio>%=
** Date Monitors
*** =Date Format Alias RefreshRate=

 - Format is a time format string, as accepted by the standard ISO C
   =strftime= function (or Haskell's =formatCalendarTime=).  Basically,
   if =date +"my-string"= works with your command then =Date= will handle
   it correctly.

 - Timezone changes are picked up automatically every minute.

 - Sample usage:

   #+begin_src haskell
     Run Date "%a %b %_d %Y <fc=#ee9a00>%H:%M:%S</fc>" "date" 10
   #+end_src

*** =DateZone Format Locale Zone Alias RefreshRate=

 A variant of the =Date= monitor where one is able to explicitly set the
 time-zone, as well as the locale.

 - The format of =DateZone= is exactly the same as =Date=.

 - If =Locale= is =""= (the empty string) the default locale of the
   system is used, otherwise use the given locale. If there are more
   instances of =DateZone=, using the empty string as input for =Locale=
   is not recommended.

 - =Zone= is the name of the =TimeZone=. It is assumed that the time-zone
   database is stored in =/usr/share/zoneinfo/=. If the empty string is
   given as =Zone=, the default system time is used.

 - Sample usage:

   #+begin_src haskell
     Run DateZone "%a %H:%M:%S" "de_DE.UTF-8" "Europe/Vienna" "viennaTime" 10
   #+end_src
** Disk Monitors
*** =DiskU Disks Args RefreshRate=

 - Aliases to =disku=

 - Disks: list of pairs of the form (device or mount point, template),
   where the template can contain =<size>=, =<free>=, =<used>=, =<freep>=
   or =<usedp>=, =<freebar>=, =<freevbar>=, =<freeipat>=, =<usedbar>=,
   =<usedvbar>= or =<usedipat>= for total, free, used, free percentage
   and used percentage of the given file system capacity.

 - Thresholds refer to usage percentage.

 - Args: default monitor arguments. =-t/--template= is ignored. Plus

   - =--free-icon-pattern=: dynamic string for free disk space in
     =freeipat=.
   - =--used-icon-pattern=: dynamic string for used disk space in
     =usedipat=.

 - Default template: none (you must specify a template for each file
   system).

 - Example:

   #+begin_src haskell
     DiskU [("/", "<used>/<size>"), ("sdb1", "<usedbar>")]
           ["-L", "20", "-H", "50", "-m", "1", "-p", "3"]
           20
   #+end_src

*** =DiskIO Disks Args RefreshRate=

 - Aliases to =diskio=

 - Disks: list of pairs of the form (device or mount point, template),
   where the template can contain =<total>=, =<read>=, =<write>= for
   total, read and write speed, respectively, as well as =<totalb>=,
   =<readb>=, =<writeb>=, which report number of bytes during the last
   refresh period rather than speed. There are also bar versions of each:
   =<totalbar>=, =<totalvbar>=, =<totalipat>=, =<readbar>=, =<readvbar>=,
   =<readipat>=, =<writebar>=, =<writevbar>=, and =<writeipat>=; and
   their "bytes" counterparts: =<totalbbar>=, =<totalbvbar>=,
   =<totalbipat>=, =<readbbar>=, =<readbvbar>=, =<readbipat>=,
   =<writebbar>=, =<writebvbar>=, and =<writebipat>=.

 - Thresholds refer to speed in b/s

 - Args: default monitor arguments. =-t/--template= is ignored. Plus

   - =--total-icon-pattern=: dynamic string for total disk I/O in
     =<totalipat>=.
   - =--write-icon-pattern=: dynamic string for write disk I/O in
     =<writeipat>=.
   - =--read-icon-pattern=: dynamic string for read disk I/O in
     =<readipat>=.

 - Default template: none (you must specify a template for each file
   system).

 - Example:

   #+begin_src haskell
     DiskIO [("/", "<read> <write>"), ("sdb1", "<total>")] [] 10
   #+end_src

** Keyboard Monitors
*** =Kbd Opts=

 - Registers to XKB/X11-Events and output the currently active keyboard
   layout. Supports replacement of layout names.

 - Aliases to =kbd=

 - Opts is a list of tuples:

   - first element of the tuple is the search string
   - second element of the tuple is the corresponding replacement

 - Example:

   #+begin_src haskell
     Run Kbd [("us(dvorak)", "DV"), ("us", "US")]
   #+end_src

*** =Locks=

 - Displays the status of Caps Lock, Num Lock and Scroll Lock.

 - Aliases to =locks=

 - Example:

   #+begin_src haskell
     Run Locks
   #+end_src
** Process Monitors
*** =TopProc Args RefreshRate=

 - Aliases to =top=
 - Args: default monitor arguments. The low and high thresholds (=-L= and
   =-H=) denote, for memory entries, the percent of the process memory
   over the total amount of memory currently in use and, for cpu entries,
   the activity percentage (i.e., the value of =cpuN=, which takes values
   between 0 and 100).
 - Variables that can be used with the =-t/--template= argument: =no=,
   =name1=, =cpu1=, =both1=, =mname1=, =mem1=, =mboth1=, =name2=, =cpu2=,
   =both2=, =mname2=, =mem2=, =mboth2=, ...
 - Default template: =<both1>=
 - Displays the name and cpu/mem usage of running processes (=bothn= and
   =mboth= display both, and is useful to specify an overall maximum
   and/or minimum width, using the =-m/-M= arguments. =no= gives the
   total number of processes.

*** =TopMem Args RefreshRate=

 - Aliases to =topmem=
 - Args: default monitor arguments. The low and high thresholds (=-L= and
   =-H=) denote the percent of the process memory over the total amount
   of memory currently in use.
 - Variables that can be used with the =-t/--template= argument:
   =name1=, =mem1=, =both1=, =name2=, =mem2=, =both2=, ...
 - Default template: =<both1>=
 - Displays the name and RSS (resident memory size) of running processes
   (=bothn= displays both, and is useful to specify an overall maximum
   and/or minimum width, using the =-m/-M= arguments.
** Thermal Monitors
*** =ThermalZone Number Args RefreshRate=

 - Aliases to "thermaln": so =ThermalZone 0 []= can be used in template
   as =%thermal0%=

 - Thresholds refer to temperature in degrees

 - Args: default monitor arguments

 - Variables that can be used with the =-t/--template= argument: =temp=

 - Default template: =<temp>C=

 - This plugin works only on systems with devices having thermal zone.
   Check directories in =/sys/class/thermal= for possible values of the
   zone number (e.g., 0 corresponds to =thermal_zone0= in that
   directory).

 - Example:

   #+begin_src haskell
     Run ThermalZone 0 ["-t","<id>: <temp>C"] 30
   #+end_src

*** =Thermal Zone Args RefreshRate=

 - *This plugin is deprecated. Use =ThermalZone= instead.*

 - Aliases to the Zone: so =Thermal "THRM" []= can be used in template as
   =%THRM%=

 - Args: default monitor arguments

 - Thresholds refer to temperature in degrees

 - Variables that can be used with the =-t/--template= argument: =temp=

 - Default template: =Thm: <temp>C=

 - This plugin works only on systems with devices having thermal zone.
   Check directories in /proc/acpi/thermal_zone for possible values.

 - Example:

   #+begin_src haskell
     Run Thermal "THRM" ["-t","iwl4965-temp: <temp>C"] 50
   #+end_src
** Volume Monitors
*** =Volume Mixer Element Args RefreshRate=

 - Aliases to the mixer name and element name separated by a colon. Thus,
   =Volume "default" "Master" [] 10= can be used as =%default:Master%=.
 - Args: default monitor arguments. Also accepts:

   - =-O= /string/ On string

     - The string used in place of =<status>= when the mixer element is
       on. Defaults to "[on]".
     - Long option: =--on=

   - =-o= /string/ Off string

     - The string used in place of =<status>= when the mixer element is
       off. Defaults to "[off]".
     - Long option: =--off=

   - =-C= /color/ On color

     - The color to be used for =<status>= when the mixer element is on.
       Defaults to "green".
     - Long option: =--onc=

   - =-c= /color/ Off color

     - The color to be used for =<status>= when the mixer element is off.
       Defaults to "red".
     - Long option: =--offc=

   - =--highd= /number/ High threshold for dB. Defaults to -5.0.
   - =--lowd= /number/ Low threshold for dB. Defaults to -30.0.
   - =--volume-icon-pattern= /string/ dynamic string for current volume
     in =volumeipat=.
   - =-H= /number/ High threshold for volume (in %). Defaults to 60.0.

     - Long option: =--highv=

   - =-L= /number/ Low threshold for volume (in %). Defaults to 20.0.

     - Long option: =--lowv=

   - =-h=: /string/ High string

     - The string added in front of =<status>= when the mixer element is
       on and the volume percentage is higher than the =-H= threshold.
       Defaults to "".
     - Long option: =--highs=

   - =-m=: /string/ Medium string

     - The string added in front of =<status>= when the mixer element is
       on and the volume percentage is lower than the =-H= threshold.
       Defaults to "".
     - Long option: =--mediums=

   - =-l=: /string/ Low string

     - The string added in front of =<status>= when the mixer element is
       on and the volume percentage is lower than the =-L= threshold.
       Defaults to "".
     - Long option: =--lows=

 - Variables that can be used with the =-t/--template= argument:
   =volume=, =volumebar=, =volumevbar=, =volumeipat=, =dB=, =status=,
   =volumestatus=
 - Note that =dB= might only return 0 on your system. This is known to
   happen on systems with a pulseaudio backend.
 - Default template: =Vol: <volume>% <status>=
 - Requires the package [[http://hackage.haskell.org/package/alsa-core][alsa-core]] and [[http://hackage.haskell.org/package/alsa-mixer][alsa-mixer]] installed in your
   system. In addition, to activate this plugin you must pass the
   =with_alsa= flag during compilation.

*** =Alsa Mixer Element Args=

 Like [[=Volume Mixer Element Args RefreshRate=][Volume]] but with the following differences:

 - Uses event-based refreshing via =alsactl monitor= instead of polling,
   so it will refresh instantly when there's a volume change, and won't
   use CPU until a change happens.
 - Aliases to =alsa:= followed by the mixer name and element name
   separated by a colon. Thus, =Alsa "default" "Master" []= can be used
   as =%alsa:default:Master%=.
 - Additional options (after the =--=):
   - =--alsactl=/path/to/alsactl=: If this option is not specified,
     =alsactl= will be sought in your =PATH= first, and failing that, at
     =/usr/sbin/alsactl= (this is its location on Debian systems.
     =alsactl monitor= works as a non-root user despite living in
     =/usr/sbin=.).
   - =stdbuf= (from coreutils) must be (and most probably already is) in
     your =PATH=.
** Mail Monitors
*** =Mail Args Alias=

 - Args: list of maildirs in form =[("name1","path1"),...]=. Paths may
   start with a '~' to expand to the user's home directory.

 - This plugin requires inotify support in your Linux kernel and the
   [[http://hackage.haskell.org/package/hinotify/][hinotify]] package. To activate, pass the =with_inotify= flag during
   compilation.

 - Example:

   #+begin_src haskell
     Run Mail [("inbox", "~/var/mail/inbox"),
               ("lists", "~/var/mail/lists")]
              "mail"
   #+end_src

*** =MailX Args Opts Alias=

 - Args: list of maildirs in form =[("name1","path1","color1"),...]=.
   Paths may start with a '~' to expand to the user's home directory.
   When mails are present, counts are displayed with the given name and
   color.

 - Opts is a possibly empty list of options, as flags. Possible values:
   -d dir --dir dir a string giving the base directory where maildir
   files with a relative path live. -p prefix --prefix prefix a string
   giving a prefix for the list of displayed mail counts -s suffix
   --suffix suffix a string giving a suffix for the list of displayed
   mail counts

 - This plugin requires inotify support in your Linux kernel and the
   [[http://hackage.haskell.org/package/hinotify/][hinotify]] package. To activate, pass the =with_inotify= flag during
   compilation.

 - Example:

   #+begin_src haskell
     Run MailX [("I", "inbox", "green"),
                ("L", "lists", "orange")]
               ["-d", "~/var/mail", "-p", " ", "-s", " "]
               "mail"
   #+end_src

*** =MBox Mboxes Opts Alias=

 - Mboxes a list of mbox files of the form =[("name", "path", "color")]=,
   where name is the displayed name, path the absolute or relative (to
   BaseDir) path of the mbox file, and color the color to use to display
   the mail count (use an empty string for the default).

 - Opts is a possibly empty list of options, as flags. Possible values:
   -a --all (no arg) Show all mailboxes, even if empty. -u (no arg) Show
   only the mailboxes' names, sans counts. -d dir --dir dir a string
   giving the base directory where mbox files with a relative path live.
   -p prefix --prefix prefix a string giving a prefix for the list of
   displayed mail counts -s suffix --suffix suffix a string giving a
   suffix for the list of displayed mail counts

 - Paths may start with a '~' to expand to the user's home directory.

 - This plugin requires inotify support in your Linux kernel and the
   [[http://hackage.haskell.org/package/hinotify/][hinotify]] package. To activate, pass the =with_inotify= flag during
   compilation.

 - Example. The following command look for mails in =/var/mail/inbox= and
   =~/foo/mbox=, and will put a space in front of the printed string
   (when it's not empty); it can be used in the template with the alias
   =mbox=:

   #+begin_src haskell
     Run MBox [("I ", "inbox", "red"), ("O ", "~/foo/mbox", "")]
              ["-d", "/var/mail/", "-p", " "] "mbox"
   #+end_src

*** =NotmuchMail Alias Args Rate=

 This plugin checks for new mail, provided that this mail is indexed by
 =notmuch=. In the =notmuch= spirit, this plugin checks for new *threads*
 and not new individual messages.

 - Alias: What name the plugin should have in your template string.

 - Args: A list of =MailItem= s of the form

   #+begin_src haskell
     [ MailItem "name" "address" "query"
     ...
     ]
   #+end_src

   where

   - =name= is what gets printed in the status bar before the number of
     new threads.
   - =address= is the e-mail address of the recipient, i.e. we only query
     mail that was send to this particular address (in more concrete
     terms, we pass the address to the =to:= constructor when performing
     the search). If =address= is empty, we search through all unread
     mail, regardless of whom it was sent to.
   - =query= is funneled to =notmuch search= verbatim. For the general
     query syntax, consult =notmuch search --help=, as well as
     =notmuch-search-terms(7)=. Note that the =unread= tag is *always*
     added in front of the query and composed with it via an *and*.

 - Rate: Rate with which to update the plugin (in deciseconds).

 - Example:

   - A single =MailItem= that displays all unread threads from the given
     address:

     #+begin_src haskell
       MailItem "mbs:" "soliditsallgood@mailbox.org" ""
     #+end_src

   - A single =MailItem= that displays all unread threads with
     "[My-Subject]" somewhere in the title:

     #+begin_src haskell
       MailItem "S:" "" "subject:[My-Subject]"
     #+end_src

   - A full example of a =NotmuchMail= configuration:

     #+begin_src haskell
       Run NotmuchMail "mail"  -- name for the template string
         [ -- All unread mail to the below address, but nothing that's tagged
           -- with @lists@ or @haskell@.
           MailItem "mbs:"
                    "soliditsallgood@mailbox.org"
                    "not tag:lists and not tag:haskell"

           -- All unread mail that has @[Haskell-Cafe]@ in the subject line.
         , MailItem "C:" "" "subject:[Haskell-Cafe]"

           -- All unread mail that's tagged as @lists@, but not @haskell@.
         , MailItem "H:" "" "tag:lists and not tag:haskell"
         ]
         600                   -- update every 60 seconds
     #+end_src

** Music Monitors
*** =MPD Args RefreshRate=

 - This monitor will only be compiled if you ask for it using the
   =with_mpd= flag. It needs [[http://hackage.haskell.org/package/libmpd/][libmpd]] 5.0 or later (available on Hackage).

 - Aliases to =mpd=

 - Args: default monitor arguments. In addition you can provide =-P=,
   =-S= and =-Z=, with an string argument, to represent the playing,
   stopped and paused states in the =statei= template field. The
   environment variables =MPD_HOST= and =MPD_PORT= are used to configure
   the mpd server to communicate with, unless given in the additional
   arguments =-p= (=--port=) and =-h= (=--host=). Also available:

   - =lapsed-icon-pattern=: dynamic string for current track position in
     =ipat=.

 - Variables that can be used with the =-t/--template= argument: =bar=,
   =vbar=, =ipat=, =state=, =statei=, =volume=, =length=, =lapsed=,
   =remaining=, =plength= (playlist length), =ppos= (playlist position),
   =flags= (ncmpcpp-style playback mode), =name=, =artist=, =composer=,
   =performer=, =album=, =title=, =track=, =file=, =genre=, =date=

 - Default template: =MPD: <state>=

 - Example (note that you need "--" to separate regular monitor options
   from MPD's specific ones):

   #+begin_src haskell
     Run MPD ["-t",
              "<composer> <title> (<album>) <track>/<plength> <statei> [<flags>]",
              "--", "-P", ">>", "-Z", "|", "-S", "><"] 10
   #+end_src

*** =MPDX Args RefreshRate Alias=

 Like =MPD= but uses as alias its last argument instead of "mpd".

*** =Mpris1 PlayerName Args RefreshRate=

 - Aliases to =mpris1=

 - Requires [[http://hackage.haskell.org/package/dbus][dbus]] and [[http://hackage.haskell.org/package/text][text]] packages. To activate, pass the =with_mpris=
   flag during compilation.

 - PlayerName: player supporting MPRIS v1 protocol. Some players need
   this to be an all lowercase name (e.g. "spotify"), but some others
   don't.

 - Args: default monitor arguments.

 - Variables that can be used with the =-t/--template= argument:
   =album=, =artist=, =arturl=, =length=, =title=, =tracknumber=

 - Default template: =<artist> - <title>=

 - Example:

   #+begin_src haskell
     Run Mpris1 "clementine" ["-t", "<artist> - [<tracknumber>] <title>"] 10
   #+end_src

*** =Mpris2 PlayerName Args RefreshRate=

 - Aliases to =mpris2=

 - Requires [[http://hackage.haskell.org/package/dbus][dbus]] and [[http://hackage.haskell.org/package/text][text]] packages. To activate, pass the =with_mpris=
   flag during compilation.

 - PlayerName: player supporting MPRIS v2 protocol. Some players need
   this to be an all lowercase name (e.g. "spotify"), but some others
   don't.

 - Args: default monitor arguments.

 - Variables that can be used with the =-t/--template= argument:
   =album=, =artist=, =arturl=, =length=, =title=, =tracknumber=,
   =composer=, =genre=

 - Default template: =<artist> - <title>=

 - Example:

   #+begin_src haskell
     Run Mpris2 "spotify" ["-t", "<artist> - [<composer>] <title>"] 10
   #+end_src
** Network Monitors
*** =Network Interface Args RefreshRate=

 - Aliases to the interface name: so =Network "eth0" []= can be used as
   =%eth0%=
 - Thresholds refer to velocities expressed in Kb/s
 - Args: default monitor arguments, plus:

   - =--rx-icon-pattern=: dynamic string for reception rate in =rxipat=.
   - =--tx-icon-pattern=: dynamic string for transmission rate in
     =txipat=.
   - =--up=: string used for the =up= variable value when the interface
     is up.

 - Variables that can be used with the =-t=/=--template= argument: =dev=,
   =rx=, =tx=, =rxbar=, =rxvbar=, =rxipat=, =txbar=, =txvbar=, =txipat=,
   =up=. Reception and transmission rates (=rx= and =tx=) are displayed
   by default as Kb/s, without any suffixes, but you can set the =-S= to
   "True" to make them displayed with adaptive units (Kb/s, Mb/s, etc.).
 - Default template: =<dev>: <rx>KB|<tx>KB=

*** =DynNetwork Args RefreshRate=

 - Active interface is detected automatically
 - Aliases to "dynnetwork"
 - Thresholds are expressed in Kb/s
 - Args: default monitor arguments, plus:

 - =--rx-icon-pattern=: dynamic string for reception rate in =rxipat=.
 - =--tx-icon-pattern=: dynamic string for transmission rate in =txipat=
 - =--devices=: comma-separated list of devices to show.

 - Variables that can be used with the =-t=/=--template= argument:
   =dev=, =rx=, =tx=, =rxbar=, =rxvbar=, =rxipat=, =txbar=, =txvbar=,
   =txipat=.

 Reception and transmission rates (=rx= and =tx=) are displayed in Kbytes
 per second, and you can set the =-S= to "True" to make them displayed
 with units (the string "Kb/s").
 - Default template: =<dev>: <rx>KB|<tx>KB=
 - Example of usage of =--devices= option:

     =["--", "--devices", "wlp2s0,enp0s20f41"]=

*** =Wireless Interface Args RefreshRate=

 - If set to "", first suitable wireless interface is used.
 - Aliases to the interface name with the suffix "wi": thus,
   =Wireless   "wlan0" []= can be used as =%wlan0wi%=, and
   =Wireless "" []= as =%wi%=.
 - Args: default monitor arguments, plus:

   - =--quality-icon-pattern=: dynamic string for connection quality in
     =qualityipat=.

 - Variables that can be used with the =-t=/=--template= argument:
   =ssid=, =signal=, =quality=, =qualitybar=, =qualityvbar=,
   =qualityipat=
 - Thresholds refer to link quality on a =[0, 100]= scale. Note that
   =quality= is calculated from =signal= (in dBm) by a possibly lossy
   conversion. It is also not taking into account many factors such as
   noise level, air busy time, transcievers' capabilities and the others
   which can have drastic impact on the link performance.
 - Default template: =<ssid> <quality>=
 - To activate this plugin you must pass the =with_nl80211= or the
   =with_iwlib= flag during compilation.
** Weather Monitors
*** =Weather StationID Args RefreshRate=

 - Aliases to the Station ID: so =Weather "LIPB" []= can be used in
   template as =%LIPB%=
 - Thresholds refer to temperature in the selected units
 - Args: default monitor arguments, plus:

   - =--weathers= /string/ : display a default string when the =weather=
     variable is not reported.

     - short option: =-w=
     - Default: ""

   - =--useManager= /bool/ : Whether to use one single manager per
     monitor for managing network connections or create a new one every
     time a connection is made.

     - Short option: =-m=
     - Default: True

 - Variables that can be used with the =-t/--template= argument:
   =station=, =stationState=, =year=, =month=, =day=, =hour=,
   =windCardinal=, =windAzimuth=, =windMph=, =windKnots=, =windMs=,
   =windKmh= =visibility=, =skyCondition=, =weather=, =tempC=, =tempF=,
   =dewPointC=, =dewPointF=, =rh=, =pressure=
 - Default template: =<station>: <tempC>C, rh <rh>% (<hour>)=
 - Retrieves weather information from http://tgftp.nws.noaa.gov. Here is
   an [[https://tgftp.nws.noaa.gov/data/observations/metar/decoded/CYLD.TXT][example]], also showcasing the kind of information that may be
   extracted. Here is [[https://weather.rap.ucar.edu/surface/stations.txt][a sample list of station IDs]].

*** =WeatherX StationID SkyConditions Args RefreshRate=

 - Works in the same way as =Weather=, but takes an additional argument,
   a list of pairs from sky conditions to their replacement (typically a
   unicode string or an icon specification).
 - Use the variable =skyConditionS= to display the replacement of the
   corresponding sky condition. All other =Weather= template variables
   are available as well.

 For example:

 #+begin_src haskell
   WeatherX "LEBL"
            [ ("clear", "🌣")
            , ("sunny", "🌣")
            , ("mostly clear", "🌤")
            , ("mostly sunny", "🌤")
            , ("partly sunny", "⛅")
            , ("fair", "🌑")
            , ("cloudy","☁")
            , ("overcast","☁")
            , ("partly cloudy", "⛅")
            , ("mostly cloudy", "🌧")
            , ("considerable cloudiness", "⛈")]
            ["-t", "<fn=2><skyConditionS></fn> <tempC>° <rh>%  <windKmh> (<hour>)"
            , "-L","10", "-H", "25", "--normal", "black"
            , "--high", "lightgoldenrod4", "--low", "darkseagreen4"]
            18000
 #+end_src

 As mentioned, the replacement string can also be an icon specification,
 such as =("clear", "<icon=weather-clear.xbm/>")=.
** Other Monitors
*** =Brightness Args RefreshRate=

 - Aliases to =bright=

 - Args: default monitor arguments, plus the following specif ones:

   - =-D=: directory in =/sys/class/backlight/= with files in it
     (default: "acpi_video0")
   - =-C=: file with the current brightness (default: actual_brightness)
   - =-M=: file with the maximum brightness (default: max_brightness)
   - =--brightness-icon-pattern=: dynamic string for current brightness
     in =ipat=.

 - Variables that can be used with the =-t/--template= argument:
   =vbar=, =percent=, =bar=, =ipat=

 - Default template: =<percent>=

 - Example:

   #+begin_src haskell
     Run Brightness ["-t", "<bar>"] 60
   #+end_src

*** =CatInt n filename=

 - Reads and displays an integer from the file whose path is =filename=
   (especially useful with files in =/sys=).

 - Aliases as =catn= (e.g. =Cat 0= as =cat0=, etc.) so you can have
   several.

 - Example:

   #+begin_src haskell
     Run CatInt 0 "/sys/devices/platform/thinkpad_hwmon/fan1_input" [] 50
   #+end_src

*** =CommandReader "/path/to/program" Alias=

 - Runs the given program, and displays its standard output.

*** =Uptime Args RefreshRate=

 - Aliases to =uptime=
 - Args: default monitor arguments. The low and high thresholds refer to
   the number of days.
 - Variables that can be used with the =-t/--template= argument: =days=,
   =hours=, =minutes=, =seconds=. The total uptime is the sum of all
   those fields. You can set the =-S= argument to =True= to add units to
   the display of those numeric fields.
 - Default template: =Up: <days>d <hours>h <minutes>m=

*** =UVMeter=

 - Aliases to "uv" + station id. For example: =%uv Brisbane%= or
   =%uv   Alice Springs%=

 - Args: default monitor arguments, plus:

   - =--useManager= /bool/ : Whether to use one single manager per
     monitor for managing network connections or create a new one every
     time a connection is made.

     - Short option: =-m=
     - Default: True

 - /Reminder:/ Keep the refresh rate high, to avoid making unnecessary
   requests every time the plug-in is run.

 - Station IDs can be found here:
   http://www.arpansa.gov.au/uvindex/realtime/xml/uvvalues.xml

 - Example:

   #+begin_src haskell
     Run UVMeter "Brisbane" ["-H", "3", "-L", "3", "--low", "green", "--high", "red"] 900
   #+end_src

* Interfacing with Window Managers

  Listed below are ways to interface xmobar with your window manager
  of choice.

** Property-based Logging
*** =XMonadLog=

 - Aliases to XMonadLog

 - Displays information from xmonad's =_XMONAD_LOG=. You can use this by
   using functions from the [[https://hackage.haskell.org/package/xmonad-contrib-0.16/docs/XMonad-Hooks-DynamicLog.html][XMonad.Hooks.DynamicLog]] module. By using the
   =xmonadPropLog= function in your logHook, you can write the the above
   property. The following shows a minimal xmonad configuration that
   spawns xmobar and then writes to the =_XMONAD_LOG= property.

   #+begin_src haskell
     main = do
       spawn "xmobar"
       xmonad $ def
         { logHook = dynamicLogString defaultPP >>= xmonadPropLog
         }
   #+end_src

   This plugin can be used as a sometimes more convenient alternative to
   =StdinReader=. For instance, it allows you to (re)start xmobar outside
   xmonad.

*** =UnsafeXMonadLog=

 - Aliases to UnsafeXMonadLog
 - Displays any text received by xmobar on the =_XMONAD_LOG= atom.
 - Will not do anything to the text received. This means you can pass
   xmobar dynamic actions. Be careful to escape (using =<raw=…>=) or
   remove tags from dynamic text that you pipe through to xmobar in this
   way.

 - Sample usage: Send the list of your workspaces, enclosed by actions
   tags, to xmobar.  This enables you to switch to a workspace when you
   click on it in xmobar!

   #+begin_src shell
     <action=`xdotool key alt+1`>ws1</action> <action=`xdotool key alt+1`>ws2</action>
   #+end_src

 - If you use xmonad, It is advised that you still use =xmobarStrip= for
   the =ppTitle= in your logHook:

   #+begin_src haskell
     myPP = defaultPP { ppTitle = xmobarStrip }
     main = xmonad $ def
       { logHook = dynamicLogString myPP >>= xmonadPropLog
       }
   #+end_src

*** =XPropertyLog PropName=

 - Aliases to =PropName=
 - Reads the X property named by =PropName= (a string) and displays its
   value. The [[https://github.com/jaor/xmobar/raw/master/examples/xmonadpropwrite.hs][examples/xmonadpropwrite.hs script]] in xmobar's distribution
   can be used to set the given property from the output of any other
   program or script.

*** =UnsafeXPropertyLog PropName=

 - Aliases to =PropName=
 - Same as =XPropertyLog= but the input is not filtered to avoid
   injection of actions (cf. =UnsafeXMonadLog=). The program writing the
   value of the read property is responsible of performing any needed
   cleanups.

*** =NamedXPropertyLog PropName Alias=

 - Aliases to =Alias=
 - Same as =XPropertyLog= but a custom alias can be specified.

*** =UnsafeNamedXPropertyLog PropName Alias=

 - Aliases to =Alias=
 - Same as =UnsafeXPropertyLog=, but a custom alias can be specified.

** Logging via Stdin
*** =StdinReader=

 - Aliases to StdinReader
 - Displays any text received by xmobar on its standard input.
 - Strips actions from the text received. This means you can't pass
   dynamic actions via stdin. This is safer than =UnsafeStdinReader=
   because there is no need to escape the content before passing it to
   xmobar's standard input.

*** =UnsafeStdinReader=

 - Aliases to UnsafeStdinReader
 - Displays any text received by xmobar on its standard input.
 - Similar to [[=UnsafeXMonadLog=][UnsafeXMonadLog]], in the sense that it does not strip any
   actions from the received text, only using =stdin= and not a property
   atom of the root window. Please be equally carefully when using this
   as when using =UnsafeXMonadLog=!

** Pipe-based Logging
*** =PipeReader "default text:/path/to/pipe" Alias=

 - Reads its displayed output from the given pipe.
 - Prefix an optional default text separated by a colon
 - Expands environment variables in the first argument of syntax =${VAR}=
   or =$VAR=

*** =MarqueePipeReader "default text:/path/to/pipe" (length, rate, sep) Alias=

 - Generally equivalent to PipeReader

 - Text is displayed as marquee with the specified length, rate in 10th
   seconds and separator when it wraps around

   #+begin_src haskell
     Run MarqueePipeReader "/tmp/testpipe" (10, 7, "+") "mpipe"
   #+end_src

 - Expands environment variables in the first argument

*** =BufferedPipeReader Alias [(Timeout, Bool, "/path/to/pipe1"), ..]=

 - Display data from multiple pipes.

 - Timeout (in tenth of seconds) is the value after which the previous
   content is restored i.e. if there was already something from a
   previous pipe it will be put on display again, overwriting the current
   status.

 - A pipe with Timeout of 0 will be displayed permanently, just like
   =PipeReader=

 - The boolean option indicates whether new data for this pipe should
   make xmobar appear (unhide, reveal). In this case, the Timeout
   additionally specifies when the window should be hidden again. The
   output is restored in any case.

 - Use it for OSD-like status bars e.g. for setting the volume or
   brightness:

   #+begin_src haskell
     Run BufferedPipeReader "bpr"
         [ (  0, False, "/tmp/xmobar_window"  )
         , ( 15,  True, "/tmp/xmobar_status"  )
         ]
   #+end_src

   Have your window manager send window titles to =/tmp/xmobar_window=.
   They will always be shown and not reveal your xmobar. Sending some
   status information to =/tmp/xmobar_status= will reveal xmonad for 1.5
   seconds and temporarily overwrite the window titles.

 - Take a look at [[http://github.com/jaor/xmobar/raw/master/examples/status.sh][examples/status.sh]]

 - Expands environment variables for the pipe path

** Handle-based Logging
*** =HandleReader Handle Alias=

 - Display data from a Haskell =Handle=

 - This plugin is only useful if you are running xmobar from another
   Haskell program like XMonad.

 - You can use =System.Process.createPipe= to create a pair of =read= &
   =write= Handles. Pass the =read= Handle to HandleReader and write your
   output to the =write= Handle:

   #+begin_src haskell
     (readHandle, writeHandle) <- createPipe
     xmobarProcess <- forkProcess $ xmobar myConfig
             { commands =
                 Run (HandleReader readHandle "handle") : commands myConfig
             }
     hPutStr writeHandle "Hello World"
   #+end_src

** Software Transactional Memory

   When invoking xmobar from other Haskell code it can be easier and
   more performant to use shared memory.  The following plugins
   leverage =Control.Concurrent.STM= to realize these gains for xmobar.

*** =QueueReader (TQueue a) (a -> String) String=

 - Display data from a Haskell =TQueue a=.

 - This plugin is only useful if you are running xmobar from another
   haskell program like xmonad.

 - You should make an =IO= safe =TQueue a= with =Control.Concurrent.STM.newTQueueIO=.
   Write to it from the user code with =writeTQueue=, and read with =readTQueue=.
   A common use is to overwite =ppOutput= from =XMonad.Hooks.DynamicLog= as shown
   below.

   #+begin_src haskell
     main :: IO ()
     main = do
       q <- STM.newTQueueIO @String
       bar <- forkIO $ xmobar myConf
         { commands = Run (QueueReader q id "XMonadLog") : commands myConf }
       xmonad $ def { logHook = logWorkspacesToQueue q }

     logWorkspacesToQueue :: STM.TQueue String -> X ()
     logWorkspacesToQueue q =
       dynamicLogWithPP def { ppOutput = STM.atomically . STM.writeTQueue q }
       where
         -- Manage the PrettyPrinting configuration here.
         ppLayout' :: String -> String
         ppLayout' "Spacing Tall"        = xpm "layout-spacing-tall"
         ppLayout' "Spacing Mirror Tall" = xpm "layout-spacing-mirror"
         ppLayout' "Spacing Full"        = xpm "layout-full"
         ppLayout' x = x

         icon :: String -> String
         icon path = "<icon=" ++ path ++ "/>"

         xpm :: String -> String
         xpm = icon . (++ ".xpm")
   #+end_src

* Executing External Commands

  In order to execute an external command you can either write the
  command name in the template, in this case it will be executed
  without arguments, or you can configure it in the "commands"
  configuration option list with the Com template command:

  =Com ProgramName Args Alias RefreshRate=

  - ProgramName: the name of the program
  - Args: the arguments to be passed to the program at execution time
  - RefreshRate: number of tenths of second between re-runs of the
    command. A zero or negative rate means that the command will be
    executed only once.
  - Alias: a name to be used in the template. If the alias is en empty
    string the program name can be used in the template.

  E.g.:

  #+begin_src haskell
    Run Com "uname" ["-s","-r"] "" 0
  #+end_src

  can be used in the output template as =%uname%= (and xmobar will call
  /uname/ only once), while

  #+begin_src haskell
    Run Com "date" ["+\"%a %b %_d %H:%M\""] "mydate" 600
  #+end_src

  can be used in the output template as =%mydate%=.

  Sometimes, you don't mind if the command executed exits with an
  error, or you might want to display a custom message in that
  case. To that end, you can use the =ComX= variant:

    =ComX ProgramName Args ExitMessage Alias RefreshRate=

  Works like =Com=, but displaying =ExitMessage= (a string) if the
  execution fails. For instance:

  #+begin_src haskell
    Run ComX "date" ["+\"%a %b %_d %H:%M\""] "N/A" "mydate" 600
  #+end_src

  will display "N/A" if for some reason the =date= invocation fails.

* The DBus Interface

  When compiled with the optional =with_dbus= flag, xmobar can be
  controlled over dbus. All signals defined in [[https://github.com/jaor/xmobar/blob/master/src/Xmobar/System/Signal.hs][src/Signal.hs]] as =data
  SignalType= can now be sent over dbus to xmobar. Due to current
  limitations of the implementation only one process of xmobar can
  acquire the dbus. This is handled on a first-come-first-served
  basis, meaning that the first process will get the dbus
  interface. Other processes will run without further problems, yet
  have no dbus interface.

  - Bus Name: =org.Xmobar.Control=
  - Object Path: =/org/Xmobar/Control=
  - Member Name: Any of SignalType, e.g. =string:Reveal=
  - Interface Name: =org.Xmobar.Control=

  An example using the =dbus-send= command line utility:

  #+begin_src shell
  dbus-send \
      --session \
      --dest=org.Xmobar.Control \
      --type=method_call \
      --print-reply \
      '/org/Xmobar/Control' \
      org.Xmobar.Control.SendSignal \
      "string:Toggle 0"
  #+end_src

  It is also possible to send multiple signals at once:

  #+begin_src shell
    # send to another screen, reveal and toggle the persistent flag
    dbus-send [..] \
        "string:ChangeScreen 0" "string:Reveal 0" "string:TogglePersistent"
  #+end_src

  The =Toggle=, =Reveal=, and =Hide= signals take an additional integer
  argument that denotes an initial delay, in tenths of a second,
  before the command takes effect.

** Example for using the DBus IPC interface with XMonad

   Bind the key which should {,un}map xmobar to a dummy value. This is
   necessary for {,un}grabKey in xmonad.

   #+begin_src haskell
     ((0, xK_Alt_L), pure ())
   #+end_src

   Also, install =avoidStruts= layout modifier from
   =XMonad.Hooks.ManageDocks=

   Finally, install these two event hooks (=handleEventHook= in =XConfig=)
   =myDocksEventHook= is a replacement for =docksEventHook= which reacts
   on unmap events as well (which =docksEventHook= doesn't).

   #+begin_src haskell
     import qualified XMonad.Util.ExtensibleState as XS

     data DockToggleTime = DTT { lastTime :: Time } deriving (Eq, Show, Typeable)

     instance ExtensionClass DockToggleTime where
         initialValue = DTT 0

     toggleDocksHook :: Int -> KeySym -> Event -> X All
     toggleDocksHook to ks ( KeyEvent { ev_event_display = d
                                     , ev_event_type    = et
                                     , ev_keycode       = ekc
                                     , ev_time          = etime
                                     } ) =
             io (keysymToKeycode d ks) >>= toggleDocks >> return (All True)
         where
         toggleDocks kc
             | ekc == kc && et == keyPress = do
                 safeSendSignal ["Reveal 0", "TogglePersistent"]
                 XS.put ( DTT etime )
             | ekc == kc && et == keyRelease = do
                 gap <- XS.gets ( (-) etime . lastTime )
                 safeSendSignal [ "TogglePersistent"
                             , "Hide " ++ show (if gap < 400 then to else 0)
                             ]
             | otherwise = return ()

         safeSendSignal s = catchX (io $ sendSignal s) (return ())
         sendSignal    = withSession . callSignal
         withSession mc = connectSession >>= \c -> callNoReply c mc >> disconnect c
         callSignal :: [String] -> MethodCall
         callSignal s = ( methodCall
                         ( objectPath_    "/org/Xmobar/Control" )
                         ( interfaceName_ "org.Xmobar.Control"  )
                         ( memberName_    "SendSignal"          )
                     ) { methodCallDestination = Just $ busName_ "org.Xmobar.Control"
                         , methodCallBody        = map toVariant s
                         }

     toggleDocksHook _ _ _ = return (All True)

     myDocksEventHook :: Event -> X All
     myDocksEventHook e = do
         when (et == mapNotify || et == unmapNotify) $
             whenX ((not `fmap` (isClient w)) <&&> runQuery checkDock w) refresh
         return (All True)
         where w  = ev_window e
             et = ev_event_type e
   #+end_src
