How to open terminal output with a texteditor without the creation of a new file?

Many programs conventionally use - to mean standard input or standard output. Thus, you can open the screen output of a command in nano using - as the file name, as in:

ls | nano -

This will only work if your program does support that convention. This includes nano and vi on the terminal. Even the graphical text editor gedit supports it. However, pluma or mousepad do not support it, and instead will be instructed to create a regular file named -. In other cases, you cannot get around creating a regular intermediate file first.

If viewing with tilde is really needed, you may script your idea
Create a function in your .bashrc

function tildeIt () {
  tmpfile=$(mktemp)
  "$@" > $tmpfile
  tilde $tmpfile
  rm $tmpfile
}

# $@ is all words typed after tildeIt
# mktemp creates a temp file and returns his fullname

Reload .bashrc

source ~/.bashrc

Usage

tildeIt command -option

If you have vipe, you can do

ls | vipe >/dev/null

The program vipe (which I believe stands for either vi pipe or view pipe) reads standard in, opens $EDITOR on it, and writes whatever is left when you save-and-quit to standard out.