How to invoke vim editor and pipe output to bash

Question

Sometimes I need to write text and then pipe that text into another command. My usual workflow goes something like this:

vim
# I edit and save my file as file.txt
cat file.txt | pandoc -o file.pdf # pandoc is an example 
rm file.txt

I find this cumbersome and seeking to learn bash scripting I'd like to make the process much simpler by writing a command which fires open an editor and when the editor closes pipe the output of the editor to stdout. Then I'd be able to run the command as quickedit | pandoc -o file.pdf.

I'm not sure how this would work. I already wrote a function to automate this by following the exact workflow above plus some additions. It generates a random string to act as a filename and passes that to vim when the function is invoked. When the user exits vim by saving the file, the function prints the file to the console and then deletes the file.

function quickedit {
    filename="$(cat /dev/urandom | env LC_CTYPE=C tr -cd 'a-f0-9' | head -c 32)"
    vim $filename
    cat $filename
    rm $filename
}
# The problem:
# => Vim: Warning: Output is not to a terminal

The problem I soon encountered is that when I do something like quickedit | command vim itself can't be used as an editor because all output is constrained to the pipe.

I'm wondering if there are any workarounds to this, so that I could pipe the output of my quickedit function. The suboptimal alternative is to fire up a separate editor, say sublime text, but I really want to stay in the terminal.

Answer 1

vipe is a program for editing pipelines:

command1 | vipe | command2

You get an editor with the complete output of command1, and when you exit, the contents are passed on to command2 via the pipe.

In this case, there's no command1. So, you could do:

: | vipe | pandoc -o foo.pdf

Or:

vipe <&- | pandoc -o foo.pdf

vipe picks up on the EDITOR and VISUAL variables, so you can use those to get it to open Vim.

If you've not got it installed, vipe is available in the moreutils package; sudo apt-get install moreutils, or whatever your flavour's equivalent is.

Answer 2

You can do this from within Vim:

:w !pandoc -o file.pdf

Or even write the buffer into a complex pipeline:

:w !grep pattern | somecommand > file.txt

And then you can exit Vim without saving:

:q!

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However, considering your specific use case, there is probably a better solution by using vi as your command line editor. Assuming you use bash:

set -o vi

This sets your keybindings to vi. So you can edit your commands right on the command line with basic vi keybindings by pressing <Esc> and then typing vi commands such as x, cw, etc. (You can get back in insert mode by pressing i.)

Even better, and more relevant to this question, you can open Vim to create your command line content directly. Just type <Esc>v and you will get an empty Vim buffer. When you save and exit, that is the command on your command line and it is immediately run. This is much much more flexible than editing on the command line directly as you can write a whole mini-script if you want.

---

So, for example, if you want to write some tricky text and pipe it into pandoc immediately, you could just type:

<Esc>v

Then edit the Vim buffer until you have something like:

cat <<EOF | pandoc -o file.pdf
stuff for pandoc
more stuff for pandoc
EOF

Then save and exit (with :x) and the whole thing will be run as a shell command.

It will also be available in your shell's command history.

Answer 3

Running in a pipeline

Try:

quickedit() (  trap 'rm ~/temp$$' exit; vim ~/temp$$ >/dev/tty; cat ~/temp$$ )

The key is that, to be able to use vim normally, vim needs stdout to be the terminal. We accomplish that here with the redirect >/dev/tty.

For purposes of security, I put the temporary file in the user's home directory. For more on this, see Greg's FAQ Question 062. This eliminates the need to use an obscure file name.

Example:

When vim opens, I type This function succeeded. and save the file. The result on the screen looks like:

$ quickedit | grep succeeded
This function succeeded.

Even though the output of quickedit is redirected to a pipeline, vim still works normally because we have given it direct access to /dev/tty.

Running a program from within vim

As I mentioned in the comments, vim can pipe a file to a command. From within vim, for example, issue the command :w !pandoc -o file.pdf (Note: the space between w and ! is essential).

Answer 4

Make sure that vim is set as your default editor (e. g. export EDITOR=vim in your .bash_profile or .bashrc. Then, at any prompt, you can type Ctrl-X followed by Ctrl-E. This will open your current command line in your configured editor (e. g. vim). Make your edits, save and exit, and the command will be executed as though you had typed it on the command line, including pipelines and the like.

Answer 5

vim, vi, vile, emacs, all have support to pipe their buffer or even pieces of buffer (e.g line selection) into filters and commands. This is powerful to either help you in editing files, as the classic utilities become editing assistants, or to perform tasks from within the editor, using text files to memorize complete commands that you execute by cursor selection or motion, and so on. The ! character is a typical trigger for that. Read vi manual and look for this entry. With a portable customized configuration, such editors become a handy off-road toolkit useable despite poor network or graphical capabilities, stable over time (life-time). They are worth learning deeply, one of them may become your best friend.