Simple Tray Icon Tool

Question

I wrote a simple and general tray icon tool, which can be used for general notifications. You can get it from my github.
When started it waits for command on the standard input. Three commands are accepted:
icon <file>: sets the icon from file
tooltip <text>: sets the tooltip text
hide: hides the icon altogether
Application examples:
1. Xmonad layout icons: I tried bmpanel with xmonad (going for a bit more eyecandy than xmobar), but then I loose the status info of xmonad, particulary the layout info (active window and workspaces are shown nicely using ewmh compatibility). With this tool I can define my pretty printer as
ppLayout = \x -> ("icon " ++ layoutIconPath ++ x ++ ".png")
everything else empty, and pipe the layout to trayIcon.
2. Battery monitor: A bit of parsing of the acpi output
#!/bin/bash
DIR=`dirname $0`
while true; do
acpiOutput=(`acpi`)
status=${acpiOutput[2]}
status=${status:0:-1}
level=${acpiOutput[3]}
level=${level:0:-1}
timeRemaining=${acpiOutput[4]}
if [[ $status == Charging ]]; then
icon=$DIR/icons/battery-0.png
else
icon=$DIR/icons/battery-${level}.png
fi
echo icon $icon
echo tooltip $status, ${level}%, $timeRemaining
sleep 30
done | trayIcon
3. Mail checking
#!/bin/bash
DIR=`dirname $0`
while sleep 30; do $DIR/imap.py; done | trayIcon
where imap.py is this script adapted for producing the trayIcon commands.
I hope you find it useful and come up with more applications.
PS: If you are intereseted I can share the icons I use.

Answer 1

On the one hand, if you don't specify an icon nothing will be shown (even if a tooltip is specified). On the other hand, if stdin is closed the program terminates, so using echo is not appropriate. Try this "interactive session":
$ trayIcon
icon /usr/share/icons/hicolor/16x16/apps/firefox.png
tooltip test