VI everywhere, what's your superpower

By Michael Milewski

Abstract

“Once you learn VI bindings, they will be stuck with you for life”

and you will want to use them everywhere! This is an exploration of all the places you can use them, from the command line, language REPL to your database console, browser and program input, even ways of adding them to places they don’t exist. Even if VI has always been on your TODO list, some tips on how to get started in learning VI bindings from someone who is pragmatic and does NOT use VIM as their editor, just VI bindings in every place you would least expect.

The Ruby version

This presentation at June Ruby Melbourne meetup was given with a bit of a ruby spin. Talk can be watched here


## Key takeaways

  • by default you are using EMACS bindings on your command line 

    set -o | egrep -e 'emacs|vi '

emacs          	on
vi             	off

  • you can turn VI bindings on with the following command 

    set -o vi

set -o | egrep -e 'emacs|vi '

emacs          	off
vi             	on

  • you can now use all the handy VI bindings like the following 

    w        # jump a word
5w       # jump 5 words
d2w      # delete 2 words
$        # jump to end of line (like regex)
^        # jump to beginning of line (like regex)
ct;      # change to `;` character
u        # undo
y$       # yank (copy) to end of line
p        # paste what you have yanked
h j k l  # h - left, j - down, k - up, l - right

  • How to learn VI bindings? come up with a script like above and just rote learn it. Then when someone teaches you a new binding, come up with a script and learn to use it too. It only takes 5 minutes a day of practice for about a week #7DayCodeChallenge and you will have it in muscle memory.

Script for below console demo

  • Jump 5w 5 words forward,
  • $ jump to the end of the line,
  • ^ jump to the beginning of the line,
  • d5w to delete 5 words,
  • P to paste at the cursor,
  • p to paste multiple times after the cursor,
  • u to undo multiple paste commands.

VI binding practice

  • So can I use this for the input of my program?

    Ruby

    ruby -e '
require "readline"
while line = Readline.readline("> ", true)
  p line
end'

    Python

    python3 -c '
import readline
while True:
  line = input(":")
  if line == "stop":
    break
  print("%s" % line)'

Script for below console demo

  • Using y W to yank (copy) a word,
  • then P to paste it at the cursor
  • and p to paste it after the cursor
  • and finally u to undo one of the pastes.

python readline

  • Hey I am using a programming language REPL (Read-Execute-Print Loop) or a DB console and I want VI bindings too!

    # ~/.editrc
bind -v

  • But I am on someone elses machine, or on a server in production and don’t want to set that up!

    Sure just hit

    <ESC> <ENTER> <ESC> <ENTER>

    and magically VI bindings will be there

  • What else is there? 

    /        # to go into search mode
v        # to take your command line straight into a full VI editor, when you
         # exit the command runs

Script for below console demo

  • ⎋ (⎋ = ESC) ESC to go out of insert mode and go into normal mode
  • / to search,
  • /dev to search for last command in history with text dev
  • ↩ (↩ = ENTER) ENTER to run command
  • v to open VI on the command
  • $ to jump to end of line
  • B to jump back a word
  • 10~ to swap case of next 10 characters (upcase)
  • :x↩ to quit VI and execute the command

Search and VI command line

  • I am using mongo or elxir or node which don’t use readline so I can’t get VI bindings 😢

    Use rlwrap - https://github.com/hanslub42/rlwrap

    brew install rlwrap

rlwrap --always-readline mongo
rlwrap --always-readline node
rlwrap --always-readline iex

  • hey what are you using to show which keys are being used?

    Keycaster https://github.com/keycastr/keycastr

    brew cask install keycastr

^ ⌥ ⌘ k    # to toggle it on/off

In the future

I am hoping to give this talk with a python flavour at the upcoming Melbourne Python Meetup in Melbourne - Monday 4th March

Authored By:

Michael Milewski