get $home in ubuntu

$HOME is an environment variable that contains the location of your home
directory, usually /home/$USER. The $ tells us its a variable. So assuming
your user is called DevRobot the .desktop files are placed in
/home/DevRobot/Desktop/.

If you want to know where $HOME points to, you can run the following in a 
terminal.

[ajefferiss@localhost ~]$ echo "$HOME"
/home/ajefferiss

You can use it to move around the filesystem, for example cd $HOME but
generally you wont see that because you can use ~/ to represent the
current users home directory. Or just run cd by itself to move to the
home directory.