Any shortcut for "cd .."?

Not by default (There might be some exceptions to this), there isn't. But if you use the alias command you can create a shortcut like this:

alias ..="cd .."

This will allow you to use the command .. to do cd ...

Activate the autocd option. It will let you type .. for cd .. and will actually let you use any directory as a command name and will cd to it:

shopt -s autocd

For the curious, the same exists for zsh:

setopt auto_cd

I find this useful:

up() { local p= i=${1:-1}; while (( i-- )); do p+=../; done; cd "$p$2" && pwd; }

For example, up 4 = cd ../../../..

As a bonus, `up 4`/path/to/file works in a similar way to ../../../../path/to/file.