Here’s a couple of tricks that I should always remember.
How to create a “shortcut” in Ubuntu
There is no such thing as a “shortcut” in Ubuntu, but to quickly create a symbolic link to a folder, hold down CTRL+SHIFT and drag and drop the folder onto the desktop (or wherever you want). Done. The permissions of the symbolic link are determined by the file or folder to which the symbolic link points.
How to search for a file containing some text from the command line.
Courtesy of nixcraft:
$ grep -r "text to search for" /file/location
To add a user to another group
sudo adduser username group