path: root/README

% Xmobar - A Minimalistic Text Based Status Bar
% Andrea Rossato

About
-----

[Xmobar] is a minimalistic, text based, status bar. It was designed to
work with the [XMonad] Window Manager.

It was inspired by the [Ion3] status bar, and supports similar features,
like dynamic color management, output templates, and extensibility
through plugins.

[This is a screen shot] of my desktop with [XMonad] and [Xmobar].

See `xmobar.config-sample`, distributed with the source code, for a
sample configuration.

Download
--------

You can get the [Xmobar] source code from [Hackage].

To get the darcs source run:

        darcs get http://code.haskell.org/xmobar/

The latest binary can be found here:

        http://code.haskell.org/~arossato/xmobar/xmobar-0.8.bin

A recent screen shot can be found here:

        http://code.haskell.org/~arossato/xmobar/xmobar-0.8.png

Version 0.8 requires Cabal-1.2.x, but works both with ghc-6.6.1 and
ghc-6.8.1.

[Here you can find] a source tree of xmobar-0.8 which works with
Cabal-1.1.x, but compiles only with ghc-6.6.x:

        http://code.haskell.org/~arossato/xmobar/xmobar-0.8-Cabal-1.1-ghc-6.6.tar.gz

[Here you can find]: http://code.haskell.org/~arossato/xmobar/xmobar-0.8-Cabal-1.1-ghc-6.6.tar.gz

Installation
------------

To install simply run:

        tar xvfz xmobar-0.8
        cd xmobar-0.8
        runhaskell Setup.lhs configure --prefix=/usr/local
        runhaskell Setup.lhs build
        runhaskell Setup.lhs haddock --executables # optional
        runhaskell Setup.lhs install # possibly to be run as root

Run with:

        xmobar /path/to/config &

or

        xmobar &

if you have the default configuration file saved as `~/.xmobarrc`

Configuration
-------------

### Quick Start

See `xmobar.config-sample` for an example.

For the output template:

- `%command%` will execute command and print the output. The output
  may contain markups to change the characters' color.

- `<fc=#FF0000>string</fc>` will print `string` with `#FF0000` color
  (red).

Other configuration options:

`font`
:    Name of the font to be used

`bgColor` 
:    Background color

`fgColor` 
:    Default font color

`position`
:     Top, TopW, Bottom, BottomW or Static (with x, y, width and height).

:     TopW and BottomW take 2 arguments: an alignment parameter (L for
      left, C for centered, R for Right) and an integer for the
      percentage width Xmobar window will have in respect to the
      screen width

:     For example:

:          position = Bottom C 75

:     to place Xmobar at the bottom, centered with the 75% of the screen width. 

:     Or

:          position = Static { xpos = 0 , ypos = 0, width = 1024, height = 15 }

:     or

:         position = Top

`commands`
:    For setting the options of the programs to run (optional)

`sepChar` 
:    The character to be used for indicating commands in the output
     template (default '%')

`alignSep`
:    a 2 character string for aligning text in the output template. The
     text before the first character will be align to left, the text in
     between the 2 characters will be centered, and the text after the
     second character will be align to the right. 

`template`
:    The output template

### Command Line Options

[Xmobar] can be either configured with a configuration file or with
command line options. In the second case, the command line options
will overwrite the corresponding options set in the configuration
file.

Example:

    xmobar -B white -a right -F blue -t '%LIPB%' -c '[Run Weather "LIPB" [] 36000]'

This is the list of command line options (the output of 
xmobar --help):

    Usage: xmobar [OPTION...] [FILE]
    Options:
      -h, -?        --help               This help
      -V            --version            Show version information
      -f font name  --font=font name     The font name
      -B bg color   --bgcolor=bg color   The background color. Default black
      -F fg color   --fgcolor=fg color   The foreground color. Default grey
      -o            --top                Place Xmobar at the top of the screen
      -b            --bottom             Place Xmobar at the bottom of the screen
      -a alignsep   --alignsep=alignsep  Separators for left, center and right text
                                         alignment. Default: '}{'
      -s char       --sepchar=char       The character used to separate commands in
                                         the output template. Default '%'
      -t template   --template=template  The output template
      -c commands   --commands=commands  The list of commands to be executed
    Mail bug reports and suggestions to <andrea.rossato@unibz.it>

### The Output Template

The output template must contain at least one command. [Xmobar] will
parse the template and will search for the command to be executed in
the `commands` configuration option. First an `alias` will be searched
(plugins such as Weather or Network have default aliases, see below).
After that, the command name will be tried. If a command is found, the
arguments specified in the `commands` list will be used.

If no command is found in the `commands` list, [Xmobar] will ask the
operating system to execute a program with the name found in the
template. If the execution is not successful an error will be
reported.
   
### The `commands` Configuration Option

The `commands` configuration option is a list of commands information
and arguments to be used by [Xmobar] when parsing the output template.
Each member of the list consists in a command prefixed by the `Run`
keyword. Each command has arguments to control the way [Xmobar] is going
to execute it.

The option consists in a list of commands separated by a comma and
enclosed by square parenthesis.

Example:

    [Run Memory ["-t","Mem: <usedratio>%"] 10, Run Swap [] 10]

to run the Memory monitor plugin with the specified template, and the
swap monitor plugin, with default options, every second.

The only internal available command is `Com` (see below Executing
External Commands). All other commands are provided by plugins.
[Xmobar] comes with some plugins, providing a set of system monitors,
a standard input reader, an Unix named pipe reader, and a configurable
date plugin. These plugins install the following internal commands:
`Weather`, `Network`, `Memory`, `Swap`, `Cpu`, `Battery`, `Thermal`,
`CpuFreq`, `CoreTemp`, `Date`, `StdinReader` and `PipeReader`.

To remove them see below Installing/Removing a Plugin

Other commands can be created as plugins with the Plugin
infrastructure. See below Writing a Plugin

### System Monitor Plugins

This is the description of the system monitor plugins that are
installed by default.

Each monitor has an `alias` to be used in the output template.
Monitors have default aliases.

`Weather StationID Args RefreshRate`

- aliases to the Station ID: so `Weather "LIPB" []` can be used in template as `%LIBP%`
- Args: the argument list (see below)
- Variables that can be used with the `-t`/`--template` argument: 
	    `station`, `stationState`, `year`, `month`, `day`, `hour`,
	    `wind`, `visibility`, `skyCondition`, `tempC`, `tempF`,
	    `dewPoint`, `rh`, `pressure`
- Default template: `<station>: <tempC>C, rh <rh>% (<hour>)`

`Network Interface Args RefreshRate`

- aliases to the interface name: so `Network "eth0" []` can be used as `%eth0%`
- Args: the argument list (see below)
- Variables that can be used with the `-t`/`--template` argument: 
	    `dev`, `rx`, `tx`
- Default template: `<dev>: <rx>|<tx>`

`Memory Args RefreshRate`

- aliases to `memory`
- Args: the argument list (see below)
- Variables that can be used with the `-t`/`--template` argument: 
	    `total`, `free`, `buffer`, `cache`, `rest`, `used`, `usedratio`
- Default template: `Mem: <usedratio>% (<cache>M)`

`Swap Args RefreshRate`

- aliases to `swap`
- Args: the argument list (see below)
- Variables that can be used with the `-t`/`--template` argument: 
	    `total`, `used`, `free`, `usedratio`
- Default template: `Swap: <usedratio>%`

`Cpu Args RefreshRate`

- aliases to `cpu`
- Args: the argument list (see below)
- Variables that can be used with the `-t`/`--template` argument: 
	    `total`, `user`, `nice`, `system`, `idle`
- Default template: `Cpu: <total>`

`Battery Args RefreshRate`

- aliases to `battery`
- Args: the argument list (see below)
- Variables that can be used with the `-t`/`--template` argument: 
	    `left`
- Default template: `Batt: <left>`

`Thermal Zone Args RefreshRate`

- aliases to the Zone: so `Zone "THRM" []` can be used in template as `%THRM%`
- Args: the argument list (see below)
- Variables that can be used with the `-t`/`--template` argument:
	    `temp`
- Default template: `Thm: <temp>C`
- This plugin works only on sytems with devices having thermal zone.
  Check directories in /proc/acpi/thermal_zone for possible values.
- Example: Run Thermal "THRM" ["-t","iwl4965-temp: \<temp\>C"]

`CpuFreq Args RefreshRate`

- aliases to `cpufreq`
- Args: the argument list (see below)
- Variables that can be used with the `-t`/`--template` argument:
	    `core0`, `core1`, ..,  `coreN`
- Default template: `Freq: <core0>GHz`
- This monitor requires acpi_cpufreq module to be loaded in kernel
- Example: Run CpuFreq ["-t","Freq:\<core0\>|\<core1\>GHz","-L","0","-H","2","-l","lightblue","-n","white","-h","red"] 50

`CoreTemp Args RefreshRate`

- aliases to `coretemp`
- Args: the argument list (see below)
- 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: Run CoreTemp ["-t","Temp:\<core0\>|\<core1\>C","-L","40","-H","60","-l","lightblue","-n","gray90","-h","red"] 50

### Monitor Plugins Commands Arguments

These are the arguments that can be used for internal commands in the
`commands` configuration option:

    -H number           --High=number               The high threshold
    -L number           --Low=number                The low threshold
    -h color number     --high=color number         Color for the high threshold: es "#FF0000"
    -n color number     --normal=color number       Color for the normal threshold: es "#00FF00"
    -l color number     --low=color number          Color for the low threshold: es "#0000FF"
    -t output template  --template=output template  Output template of the command.

Commands' arguments must be set as a list. Es:

    Run Weather "EGPF" ["-t","<station>: <tempC>C"] 36000

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:

    Glasgow Airport: 16.0C

### 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
- 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.

Es:

        Run Com "uname" ["-s","-r"] "" 36000

can be used in the output template as `%uname%`

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

can be used in the output template as `%mydate%`

### Other Plugins

`Date Args Alias RefreshRate`

`StdinReader`

`PipeReader "/path/to/pipe" Alias`

Plugins
-------

### Writing a Plugin

Writing a plugin for [Xmobar] should be very simple. You need to create
a data type with at least one constructor.

Next you must declare this data type an instance of the `Exec` class, by
defining the 1 needed method (alternatively `start` or `run`) and 2
optional ones (alias and rate):

        start :: e -> (String -> IO ()) -> IO ()
        run   :: e -> IO String
        rate  :: e -> Int
        alias :: e -> String

`start` must receive a callback to be used to display the `String`
produced by the plugin. This method can be used for plugins that need
to perform asynchronous actions. See `Plugins/PipeReader.hs` for an
example.

`run` can be used for simpler plugins. If you define only `run` the
plugin will be run every second. To overwrite this default you just
need to implement `rate`, which must return the number of tenth of
seconds between every successive runs. See `Plugins/HelloWorld.hs` for
an example of a plugin that runs just once, and `Plugins/Date.hs` for
one that implements `rate`.

Notice that Date could be implemented as:

        instance Exec Date where
            alias (Date _ a _) = a
            start (Date f _ r) = date f r
        
        date :: String -> Int -> (String -> IO ()) -> IO ()
        date format r callback = do go
            where go = do
                    t <- toCalendarTime =<< getClockTime
                    callback $ formatCalendarTime defaultTimeLocale format t
                    tenthSeconds r >> go

This implementation is equivalent to the one you can read in
`Plugins/Date.hs`.

`alias` is the name to be used in the output template. Default alias
will be the data type constructor.

Implementing a plugin requires importing the plugin API (the `Exec`
class definition), that is exported by `Plugins.hs`. So you just need
to import it in your module with:

        import Plugins

After that your type constructor can be used as an argument for the
Runnable type constructor `Run` in the `commands` list of the
configuration options.

This requires importing your plugin into `Config.hs` and adding you
type to the type list in the type signature of `Config.runnableTypes`.

For a very basic example see `Plugins/HelloWorld.hs` or the other
plugins that are distributed with [Xmobar].

### Installing/Removing a Plugin

Installing a plugin should require 3 steps. Here we are going to
install the HelloWorld plugin that comes with [Xmobar]:

1. import the plugin module in `Config.hs`, by adding: 
   
        import Plugins.HelloWorld

2. add the plugin data type to the list of data types in the type
   signature of `runnableTypes` in `Config.hs`. For instance, for the
   HelloWorld plugin, change `runnableTypes` into:

        runnableTypes :: (Command,(Monitors,(HelloWorld,())))
        runnableTypes = undefined

3. Rebuild and reinstall [Xmobar]. Now test it with:

        xmobar Plugins/helloworld.config

As you may see in the example configuration file, the plugin can be
used by adding, in the `commands` list:

        Run HelloWorld

and, in the output template, the alias of the plugin:

        %helloWorld%

That's it.

To remove a plugin, just remove its type from the type signature of
runnableTypes and remove the imported modules.

To remove the system monitor plugin:

1. remove, from `Config.hs`, the line

        import Plugins.Monitors

2. in `Config.hs` change

         runnableTypes :: (Command,(Monitors,()))
         runnableTypes = undefined

    to

         runnableTypes :: (Command,())
         runnableTypes = undefined

3. rebuild [Xmobar].

Credits
-------

Thanks to Robert Manea and Spencer Janssen for their help in
understanding how X works. They gave me suggestions on how to solve
many problems with [Xmobar].

Thanks to Claus Reinke for make me understand existential types (or at
least for letting me think I grasp existential types...;-). 

[Xmobar] incorporates patches from: Krzysztof Kosciuszkiewicz, Spencer
Janssen, Jens Petersen, Dmitry Kurochkin, and Lennart Kolmodin.

Useful links
------------

The [Xmobar] home page

The [XMonad] home page

[Xmobars darcs repository]

To understand the internal mysteries of Xmobar you may try reading
this tutorial [on X Window Programming in Haskell].

Author
------

Andrea Rossato 

`andrea.rossato at unibz.it`

Legal
-----

This software is released under a BSD-style license. See LICENSE for
more details.

Copyright &copy; 2007 Andrea Rossato

[This is a screen shot]: http://haskell.org/sitewiki/images/a/ae/Arossato-config.png
[Hackage]: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/xmobar
[Xmobar]: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/xmobar
[Xmobars darcs repository]: http://code.haskell.org/xmobar
[on X Window Programming in Haskell]: http://www.haskell.org/haskellwiki/X_window_programming_in_Haskell
[Ion3]: http://modeemi.fi/~tuomov/ion/
[XMonad]: http://xmonad.org