I installed eclipse (ultimate edition 3.5) in Ubuntu 12.04 via the terminal. I also installed the ADT plugin in the eclipse program via install new software. Everything has completed but eclipse is asking for the location of sdk. Where is sdk located on my computer?
You need to download Android sdk manually from Android official website.
Download the file and extract it wherever you want.
Now open your eclipse and go to Window → Preferences → Android → SDK Location and click on browse button to select the exacted sdk folder.
You can also use ADT Bundle which is preconfigured with all components in portable form
Please see here for more information.
Or best option is download ADT Bundle which contains Eclipse, ADT & Android SDK inbuilt.
Might be adb don't have execute permissions. Try below command to correct permissions.