I have a simple pair of functions which I use to go up a level based on typing the portion of the path I want to go up until:

  # When called as `argu string`, prints the closest ancestor directory which
  # contains "string". If none is found, or "string" is empty, the current
  # working directory is printed. This function is useful if you need to specify
  # a file as an argument, but the relative path to it involves moving several
  # directories up from the current directory. For example, instead of doing:
  #  $ pwd
  #  /this/is/a/very/long/directory/path/for/demonstration/purposes/
  #  $ ls ../../../../another/directory/something.log
  # You could do:
  #  $ ls `argu dir`/another/directory/something.log
  argu() {
    if [[ "$1" == "" ]]; then
        echo "`pwd`/"
        return
    fi
    echo "`pwd | sed "s/^\(.*"$1"[^/]*\)\/.*$/\1/g"`/"
  }

  # When called as `cdu string`, changes directories into the closest ancestor
  # directory of the current directory which contains "string". If none is found,
  # or "string" is empty, no changes are made to the current directory.
  cdu() {
    cd `argu $1`
  }

I also put the following in ~/.zsh/completion/_cdu so I can get tab-completion of the portions of the path:

  #compdef cdu
  _cdu_parents=$(pwd | tr '/' ' ')
  _arguments "1:parents:($_cdu_parents)"

Or bash (in ~/.bash/completion/cdu):

  # bash completion for cdu

  _cdu()
  {
    local cur prev split=false
    COMPREPLY=()
    _get_comp_words_by_ref -n : cur prev
    _dirs=$( pwd | tr '/' ' ' )
    COMPREPLY=( $( compgen -W "$_dirs" -- "$cur" ) )
  }

  complete -F _cdu cdu

  # Local variables:
  # mode: shell-script
  # sh-basic-offset: 4
  # sh-indent-comment: t
  # indent-tabs-mode: nil
  # End:
  # ex: ts=4 sw=4 et filetype=sh