Gummiband is a program launcher for the X Window System. It can be configured to show machine status (eg battery %, or the time), and to provide launch buttons (eg a button to run xterm). It provides simple drop-down menus (eg a button can show the current wifi access point, and clicking on the button opens a menu allowing a different access point to be selected).
All dynamic content should be provided by shell scripts, which Gummiband will run according to its configuration.
Gummiband is based loosely on the 'menu' program by Elliott Hughes.
The above screenshot shows Gummiband in action. It's the bar along the top, as configured by the .gummiband file shown in the terminal. The user has opened the '[Rear Audio]' menu, which is showing a drop-down menu with front and back options. In this case, the menu items are hard-coded in the configuration, but they could just as easily be taken from the output of a script.
Gummiband's source code can be downloaded from the Jessies github page. As a quick guide to getting it up and running, try this:
git clone https://github.com/software-jessies-org/jessies.git cd jessies/x11-extras/ cmake . make gummiband man ./gummiband.man ./gummiband
The gummiband.man page has some fairly exhaustive instructions on how to configure and use the program.