I have recently dug into theming my Mac which is currently on Yosemite. Since applications like Flavours isn't updated I began doing this manually. I have a dark theme almost ready for release which you can check out here. http://www.reddit.com/r/OSXTweaks/comments/2xlz58/yosemite_theme_dark/
I will do a full tutorial on how I themed Yosemite, but I would like to start with something simple. That is adding widgets to your desktop.
GeekTool 3.1 is what I use to add widget to my desktop. You can download it for free here. http://www.macosxtips.co.uk/geeklets/system/geektool-3-1-update-no-more-mac-app-store/ I will guess that you already know how to install an app on your Mac and jump right in to GeekTool.
GeekTool allows you to add what they call Geeklets to your desktop. These Geeklets allow you to add a command and set the appearance of what returns from the command. Commands I guess will be the most difficult part here, but trust me they are very simple.
Note: You can test every command in terminal before adding it to your geeklet.
Clock- To add a clock or create a clock "geeklet" start by opening GeekTool and selecting Shell and dragging it to your desktop. Inside the preference pane you will see many option. Most of these are strictly how to style the geeklet. We want to concentrate on the command as this will more likely to be the same for everyone who follows this tutorial.
Inside the command for a Clock widget we will want to type date +%I:%M or date +%H:%M. If either of these are entered you will now see a clock in the Shell you dragged to the desktop. date +%I:%M will give you 12hr time and date +%H:%M will give you 24hr time. Thats basically it, the only thing left to do is set the refresh every XX seconds. (This will set how often it updates)
Command: date +%I:%M for 12hr or date +%H:%M for 24hr
Date- Exactly how we added the clock, we will now add a date. Start by dragging a shell to your desktop, the command we will use is date '+%A%e %B' This will give you a date as shown above.
Command: date '+%A%e %B'
Weather-Same as before drag a shell to your desktop, the command for weather is
curl --silent "http://weather.yahooapis.com/forecastrss?p=38618&u=f" | grep -E '(Current Conditions:|F<BR)' | sed -e 's/Current Conditions://' -e 's/<br \/>//' -e 's/<b>//' -e 's/<\/b>//' -e 's/<BR \/>//' -e 's/<description>//' -e 's/\(.*\) F/\1° F/' -e 's/<\/>//'
This will give you the current condition and temperature. To adjust it to your weather just replace the 38618 with your zip code and the f to c if you want celsius. Basically all this script does is get the yahoo weather xml and get the description and temp.
Command: curl --silent "http://weather.yahooapis.com/forecastrss?p=38618&u=f" | grep -E '(Current Conditions:|F<BR)' | sed -e 's/Current Conditions://' -e 's/<br \/>//' -e 's/<b>//' -e 's/<\/b>//' -e 's/<BR \/>//' -e 's/<description>//' -e 's/\(.*\) F/\1° F/' -e 's/<\/>//'
Image- Sometimes you will just want an image. Maybe used as a background or separator as I used above. To achieve this drag the image icon (inside geektool) to your desktop. Once there you will see the preference panel, now instead of command you will see URL. This is where your image is you will need to add the url of the image you want. I recommend it being an image on your computer. An easy way to find the location is by going to your image, and just drag it to your terminal.app this will give you the directory the image is in. Only change is you need to put file://localhost in front of the url. You will not need to set a refresh time, as most likely the image will always be the same. If you do change the image just change the refresh time to anything and the image will update.
Thats it for now, hopefully you can get some widgets running on your desktop. If this is all still too advanced you can view already submitted GeekLets here. http://www.macosxtips.co.uk/geeklets/ these are ones users made, and are not guaranteed to work. To open them first download, then double click the .glet file.
This tutorial series will continue with a little more advanced things shortly. It won't be for everyone, but there is no documentation for this yet so I hope to provide it for those interested. If you have any issues my email is listed on my website. http://JunesiPhone.com
Want to get notified when my Yosemite theme is released? Subscribe here! http://eepurl.com/bfF_Db
Send me screenshots of your desktop I would love to see different setups! My twitter is http://Twitter.com/JunesiPhone
Previous Article - 7 Free Lockscreens