The standard convention is all sketches and all user added libraries reside in ONE folder have the name LIBRARIES and located
in " My Documents\Arduino[Libraries]"
I have no idea how it work with Linux or any non-windows OS.
EVERY TIME you install a NEW LIBRARY you must verify several things. (EVERY TIME, NO EXCEPTIONS)
1- The new library name does not contain non-allowed characters like "-" or the word "Master". These must be removed.
2- That the zip file did NOT create TWO folders with the SAME name with the actual library folder at the LOWEST level inside a
folder with the SAME name..In this case, CUT & PASTE the FILES (including the "Examples" file) into the folder with the same
name at the higher level and delete the now empty folder at the LOWEST level.
3- The "Examples" folder is in the library folder and not somewhere else.
4- The library folder is a folder in the "Libraries " folder mentioned previously which is in the "Arduino" folder which is in the "My
Documents" folder. This part may differ in other OSs that may not use the "My Documents" name for such a folder.
Once you have installed a library and done all of the above . You can can CUT & PASTE any added library into a LIBTEMP holding
folder in a different path when you want to reduce the number of items in the "File\Examples " menu and then COPY & PASTE them back into the "Libraries " folder when you want to use them. This way , you have a MASTER LIBRARY HOLDING FOLDER
(LIBTEMP) and you don't need to copy them back there since they are already there. You just delete the library from the "Libraries "
folder in the "Arduino" folder and copy & paste them there when you want to use them. I have 3 complete backups of my libraries
on three different drives plus on a 16 Gb thumb drive.