The pushd command (Section 31.7) is nice for jumping around the filesystem, but some of the commands you might type a lot, like pushd +4, are sort of a pain to type. I saw these aliases (Section 29.2) in Daniel Gilly's setup file. They looked so handy that I decided to steal them for this book. There are C shell versions in the first column and Bourne-type in the second:
alias pd pushd alias pd=pushd
alias pd2 'pushd +2' alias pd2='pushd +2'
alias pd3 'pushd +3' alias pd3='pushd +3'
alias pd4 'pushd +4' alias pd4='pushd +4'
...So, for example, to swap the fourth directory on the stack, just type pd4.
— JP