Emacs Less – Piping into Less and Editing: ‘Cannot Edit Standard Input’ Error Workarounds

emacsless

I recently learned that if I page my files with less, I can press v and open the buffer in Emacs. This works as long as I have the environment variable $EDITOR set up correctly, which in my case I have it as:

export EDITOR='env TERM=xterm-256color emacs -nw'

The above gives me the ability to load emacs within the terminal that runs less.

However, the trick above does not work when piping commands to less. When doing this, less complains with the following message:

Cannot edit standard input (press RETURN)

My question is, why does this happen? But most importantly, is there any workaround to it?

Best Answer

As it was already said, you cannot edit an input stream.

The workaround is quite obvious: save the stream to a file from within less and open the saved file. To do that while viewing, press s and give a name of a file. Then either exit less and open the file by hand, or, still from within less, type :e and give the name of the file you just saved.

Related Solutions

How to get current buffer’s filename in emacs

You can put a function like follows into your .emacs and bind it to any key you like.

(defun insert-file-name ()
  "Insert the full path file name into the current buffer."
  (interactive)
  (insert (buffer-file-name (window-buffer (minibuffer-selected-window)))))

Also see this question, it seems to be similar.

Shell – Tracking the shell path in Emacs

First, as mentioned in the comment by Robert, your snippet isn't valid. At a minimum you need either a semicolon or new line before }. The print statements are probably not correct either.

However there's enough here to guess what is going on, so I'll explain that.

When you run ansi-term, it invokes a shell with the environment variable $INSIDE_EMACS set. The shell code then does additional stuff, the main thing to redefine the function chpwd so that it prints additional stuff, which no doubt includes the current working directory. You can easily verify this by noting that on every command you probably see the current directory somewhere in the prompt area after the completion of the last command proper.

When ansi-term sees something that looks like a directory at the beginning of a line, it tracks that. So in this sense that code is not special; the directory could have been shown by any number of ways, such as adding \w to the prompt via setting environment variable PS1.

As for #2, see "Open remote file while in emacs ansi-term buffer/window: ansi-term + tramp"

Best Answer

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How to get current buffer’s filename in emacs

Shell – Tracking the shell path in Emacs

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