Ubuntu / Linux news and application reviews.

GNOME Shell CPU Temperature is an extension that displays the CPU temperature on the top bar. The extension is not new, but it never worked for me until recently when the extension got support for lm-sensors. 

For now, the extension isn't exactly customizable: you can't set which temperature is displayed or display multiple temperatures at once, but you can change the temperature unit from Celsius to Fahrenheit by editing the .js file (see the comment on line 201).

To use the extension, firstly install lm-sensors ("lm_sensors" in Fedora 15) and then use the commands below:
git clone https://github.com/xtranophilist/gnome-shell-extension-cpu-temperature.git
mkdir -p ~/.local/share/gnome-shell/extensions/temperature@xtranophilist
cp gnome-shell-extension-cpu-temperature/* ~/.local/share/gnome-shell/extensions/temperature@xtranophilist

And then restart GNOME Shell (press ALT + F2 and enter: "r").

And the second extension in this post is called Window Overlay Icons - it's a simple yet very useful extension: it displays an icon for each window in the Activities overview so it's easier to distinguish the applications / windows:

GNOME SHell overlay icons

To install it, use the commands below:
git clone https://github.com/sustmi/gnome-shell-extensions-sustmi.git
mv gnome-shell-extensions-sustmi/windowoverlay-icons ~/.local/share/gnome-shell/extensions/windowoverlay-icons@sustmidown.centrum.cz

And then restart GNOME Shell (press ALT + F2 and enter: "r").

Update: the WindowOverlay Icons extension is now available in the WebUpd8 GNOME 3 PPA. See: Autohide Top Bar Extension Finally Available For GNOME Shell 3.2 (Bonus: Hamster And Overlay Icons Extensions).