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Devil's Pie

Copyright (C) 2002-5, Ross Burton <ross@burtonini.com>

A window-matching utility, inspired by Sawfish's "Matched Windows" option and
the lack such functionality in Metacity. Metacity lacking window matching is not
a bad thing -- Metacity is a lean window manager, and window manipulation does
not have to be a window manager task.

Devil's Pie can be configured to detect windows as they are created, and match
the window to a set of rules. If the window matches the rules, it can perform a
series of actions on that window. For example, I can make X-Chat appear on all
workspaces, and make a particular xterm not appear in the pager or task list.


To build devilspie, follow the usual configure ; make ; make install steps. If
this confuses you, read INSTALL. Packages are in Debian Sarge, and I build
Debian packages of the latest released version.  These are available from

A .spec file is provided for RPM-based distributions, but I didn't write it and
don't support it.  It may or may not work.


Devil's Pie 0.13 was a complete redesign and rewrite, so everything you knew
about it is probably wrong.

Devil's Pie is configured by reading a number of files from two directories:
$HOME/.devilspie/ and $SYSCONFDIR/devilspie (typically /etc/devilspie).  Devil's
Pie will read s-expressions from every .ds file in those paths.  S-expressions
are familiar to most Emacs users and in the limited use they have in Devil's Pie
are trivially learnt by example.

The basic model is that every time a window is created, the s-expressions are
evaluated.  The window is available to the functions you call as an implicit
argument, so you can concentrate on defining the logic.

If you want to see information about every window when it is created, in
~/.devilspie/test.ds put:


When this is evaluated, the "debug" function is called and it outputs the window
title, geometry, etc.

Of course performing the same action to every window is no fun.  What if you
want XMMS to start on the second workspace?

  (if (is (application_name) "XMMS") (set_workspace 2))

The "if" function evaluates the first argument as a true/false value, and if it
is true then it evaluates the second argument, and if false it evaluates the
third argument (which can be omitted).  The "is" function compares two strings
for equality, returning true if they are identical.  The "application_name"
function returns the name of the application which created the window, and
"XMMS" is a literal string.  So if the application name is "XMMS", then the
second argument will be evaluated.  This is a call to "set_workspace" with the
integer argument 2, which moves the current window onto the second workspace.

To perform multiple actions use (begin ...):

  (if (matches (window_name) "^Character.+") (begin maximize (set_workspace 2)))

Here "matches" interprets the second argument as a regular expression and
evaluates that against the first argument.  "window_name" is the title of the
current window, and "maximize" simply maximises the current window.  So this
s-expression puts the window on workspace 2, maximised, if the window name
begins with "Character" and has more characters in (note .+ rather than .*).

I will write more documentation in the future but for now you'll have to look at
the "symbols" array in src/parser.c to see what functions are available.


Just run devilspie as a normal user. The best way is to run it in your session
(for example in Desktop Preferences -> Advanced -> Sessions -> Startup

If you are testing some s-expressions, you can specify them on the command line
to load just those files instead of the files specified above.  To turn on some
debugging information, pass --debug.