Running in xterm (or gnome-terminal) the following command sets the so-called "Icon Name":
echo -en "\e]1;some_value\a"
What does this do?
Note that it is possible to set both "Window Title" and "Icon Name" to the same value with the same command, so I don't understand how "Icon Name" could be a path to, say, an image.
A long time ago, there was a window manager called twm—actually, it still exists and runs perfectly well. Instead of minimizing a window to a bar at the bottom of the screen (or similar) like MS Windows, Mac OS X, and many modern window managers, it shrunk them to labeled icons ("iconfify").
The Wikipedia twm article has some nice pictures, such as:
The window title is what goes in the titlebar (e.g., the "Calculator" or "xterm"). The icon name is what goes under the icon when iconified (the "xclock"). Modern window managers probably all ignore the icon name because they don't use the icon UI.
A full description of both can be found in the ICCCM.
I'll talk about xterm here: it's an old piece of software and much of its terminology is now outdated. In man xterm it says:
iconName (class IconName) Specifies a label for xterm when iconified. Xterm provides no default value; some window managers may assume the application name, e.g., "xterm" Setting the iconName resource sets the icon label unless overridden by zIconBeep or the control sequences which change the window and icon labels.
That means that iconName must not be an icon image, it's just a label that's given to xterm window when it's iconified. It can be also set using -n option:
-n string This option specifies the icon name for xterm's windows. It is shorthand for specifying the "iconName" resource. Note that this is not the same as the toolkit option -name (see below). The default icon name is the application name.
After starting xterm like this, with a title != iconName I still can't see ICON string being shown after iconifying xterm window (Alt-F9 in fluxbox):
$ xterm -n ICON -T a-new-title
Digging further through xterm manpage one finds (** mine):
activeIcon (class ActiveIcon) Specifies whether or not active icon windows are to be used when the xterm window is iconified, if this feature is compiled into xterm. The active icon is a miniature representation of the content of the window and will update as the content changes. Not all window managers necessarily support application icon windows. Some window managers will allow you to enter keystrokes into the active icon window. The default is "default". Xterm accepts either a keyword (ignoring case) or the number shown in parentheses: false (0) No active icon is shown. true (1) The active icon is shown. If you are using twm, use this setting to enable active-icons. default (2) Xterm checks at startup, and shows an active icon only for window managers which it can identify and which are known to support the feature. **These are fvwm (full support), and window maker (limited).** A few other windows managers (such as twm and ctwm) support active icons, but do not support the exten- sions which allow xterm to identify the window manager.
activeIcon is probably not directly related to iconName feature, however it gives us a clue that icon-related features in xterm work correctly only with some window managers. I recommend Xephyr for testing one either fvwm or window maker as specified in the manpage:
$ Xephyr :1 -ac -screen 800x600
and in another terminal:
$ DISPLAY=:1 wmaker
Now let's start xterm inside window maker: right click -> Applications -> Terminals -> xterm. Start xterm with -n option again:
$ xterm -n ICON -T a-new-title
Right click on the title bar and choose Miniaturize. Now you can see that an xterm icon is actually labeled ICON. Bring it back by clicking on it and see that titlebar is a-new-title. The conclusion is that iconName feature works only with some window managers, most probably older ones. If you feel strong you can browse window maker source code and patch your own window manager if it doesn't support iconName.
BTW, for changing xterm icon image see this: https://superuser.com/questions/344320/how-do-i-change-the-icon-of-an-xterm.
