Fish Interactive Shell full path

With the new fishshell (v2.3) you can do set -U fish_prompt_pwd_dir_length 0. And it will use the full path. I also use dartfish for my theme. See example below:

Here's my version of prompt_pwd that should display what you're looking for:

function prompt_pwd --description 'Print the current working directory, NOT shortened to fit the prompt'
    if test "$PWD" != "$HOME"
        printf "%s" (echo $PWD|sed -e 's|/private||' -e "s|^$HOME|~|")
    else
        echo '~'
    end

end

This will display the tilde for the home directory, as usual, but removes the sed command that only pulls the first letter from each directory when you're a few directories deep.

To edit prompt_pwd use funced. It will allow you to interactively alter the function. From the command line type funced prompt_pwd. Once the prompt is displaying to your liking, use funcsave prompt_pwd to make the behavior persist in future sessions.