Useful Bash Shell Aliases

The commands depend on the OS X open features. Pretty self-explanatory:
alias _o3='open http://localhost:3000'
alias _o5='open http://localhost:5000'
alias _o8='open http://localhost:8000'
alias _opdf='cd ~/books && open "$(ls -rtu | grep pdf$ | tail -1)" && cd -'
alias 8=_o8
alias 5=_o5
alias 3=_o3
alias i=ipython
alias b=_opdf
alias _reset_digital_aliases='for i in $(echo "3,5,8,i,b" | tr "," "\n"); do unalias $i; done'
alias 0=_reset_digital_aliases