To change between existing cursor themes you need to...change the dconf setting and the alternatives setting as fantab stated.
New themes need to be added to alternatives first.
The new theme will not show up when you run sudo update-alternatives --config x-cursor-theme
You need to add it to alternatives first.
These are the steps for a downloaded theme.
- Extract from archive.
- Check for a cursor.theme file
- Move theme to /usr/share/icons
- Add to alternatives
- Select with alternatives
- Select in dconf
For a gui to manage alternatives, install galternatives.....
sudo apt-get install galternatives
A downloaded theme archive must be extracted to reveal the theme folder.
In this folder there must be cursor.theme file.
Create one using gedit, if necessary.
For an example , look at /usr/share/icons/DMZ-White/cursor.theme.
Inherits=<insert your cursor name>
Move theme folder to /usr/share/icons as described earlier by fantab
Add theme to alternatives using galternatives
Run galternatives and select x-cursor-theme in the left panel.
Click on the add button >browse
Then use the top drop down to navigate to /usr/share/icons . Start with "/" then in the left column progressively choose(double click) usr/ > share/ > icons/
Select your theme in the left column and then select cursor.theme in right column and hit the ok button.
Select your theme in galternatives and close.
Now you just need to select your new theme using a tweak tool like unity-tweak-tool, gnome-tweak-tool or ubuntu-tweak.
The tweak tools change the dconf setting shown earlier by fantab.
After changing a cursor theme you need to log out/in for it to be consistent.