How to edit content from the standard input?

Question

I would like to edit content in vim which was dynamically generated from the command-line without having the file yet.

In example:

$ echo This is example. | vim /dev/stdin
$ cat /etc/hosts | vim /dev/stdin

but it's failing with the errors:

Vim: Warning: Input is not from a terminal

Vim: Error reading input, exiting...

It is possible to achieve that?

Answer 1

You have to use - in place of the file name on the command line:

echo This is example. | vim -

The above command will open an unnamed buffer filled with the text read from the standard input.

Answer 2

This is just mostly a fun note about bash and readline, but if you set your EDITOR environment variable to vim, hitting Ctrl+x+e will open up the current line in vim. Further, if you type Meta(Alt/Opt/Esc)+Ctrl+e, bash will perform an in place expansion on the current command line, i.e.:

$ echo $EDITOR # Assuming EDITOR was set

with Meta(Alt/Opt/Esc)+Ctrl+e would become

$ echo vim # Assuming EDITOR was set

with Ctrl+x+e would become

1 echo vim # Assuming EDITOR was set
~
~
/tmp/sometmpbufferfile

Note that upon quitting vim, the contents of the vim buffer are executed on the command line.

These features become very useful for me when I want to do multi-line commands in bash such as for loops or programs requiring here statements, and provides an interesting way to save a bit of command-line history to file for later use.

So to answer the original question, you could also write,

$ This is an example

and then hit Ctrl+x+e to load it up in vim. Also you could have,

 $ $(cat /etc/hosts)

and do Meta(Alt/Opt/Esc)+Ctrl+e then Ctrl+x+e, which would put all of the hosts file on one line and load it up in vim (probably not the best use of these features--however, the usefulness of these methods can be extrapolated from the few examples discussed here).

Note that I assume that your readline is set to emacs mode. If your readline is set to vim mode you can easily discover the relevant bindings by using the command:

bind -p

and searching for edit-and-execute-command or shell-expand-line, which were respectively associated with the bindings Ctrl+x+e and Meta(Alt/Opt/Esc)+Ctrl+e.

Answer 3

In bash I've found it useful to use process substitution using the <(command) syntax, in example:

vim <(echo This is example.)
vim <(cat /etc/hosts)

See also:

• How to edit files non-interactively (e.g. in pipeline)? at Vi SE
• How to pipe the result of a grep search into a new vi file at unix SE

Answer 4

If using a pipeline to a new Vim is not a requirement, you can use Vim's ability to pull in the output of commands into the current buffer, coupled with having a non-file backed buffer (as with :new or editing a non-existent file)

:read!cat /etc/hosts in command-mode will place the output into your current buffer below the current cursor position.

Apart from having to delete the empty first line that remains when this is done on an empty buffer, this works well and is especially convenient if Vim is already running.