Best way to gain quick access to frequently used directory in linux terminal

Create a symbolic link in your home directory:

$ ln -s path/to/a/really/deeply/nested/director/my-project ~/my-project

$ cd ~/my-project

You can also take advantage of CDPATH variable.

And you could define a bash function in your $HOME/.bashrc like

 # in file ~/.bashrc
 function work() {
    cd $HOME/path/to/a/really/deeply/nested/director/my-project
 }

And recent bash or even better zsh may permit you things like

 cd **/my-project

Assuming you have only one deeply nested my-project/ directory in all your tree hierarchy. The ** is doing the equivalent of a find so can be slow.

Add a variable in your .bashrc:

MYPROJECT=path/to/a/really/deeply/nested/director/my-project

to use:

$ cd $MYPROJECT