Place the following lines in .bash_profile
.
X, Y, Z = change to your folder names.
# define favorite paths
if [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fi
shopt -s cdable_vars
export dropbox=~/Dropbox\ \(X\)
export current=~/Dropbox\ \(X\)/Y
export overleaf=~/Dropbox\ \(X\)/Y/Z
Then enjoying going directly to your favorite folders by:
cd dropbox