Edit command line in Fish

config.fish

# thanks to github.com/oh-my-fish/theme-budspencer

# Set the tmp file
set -g tmpcmdline '/tmp/'(echo %self)'_cmdline.fish'

function edit_commandline -d 'Open current command line with your editor'
  commandline > $tmpcmdline
  eval $EDITOR $tmpcmdline
  set -l IFS ''
  if [ -s $tmpcmdline ]
    commandline (sed 's|^\s*||' $tmpcmdline)
  else
    commandline ''
  end
  rm $tmpcmdline
end

# Your fish_user_key_bindings function will look different. Make sure to ADD the line:
# bind \ci 'edit_commandline'
# and replace it with the binding of your choice. You can't have multiple fish_user_key_bindings
# functions because they will overwrite.
# I made examples for vi_mode and non vi_mode use.

# Use without vi_mode
function fish_user_key_bindings
  bind \ci 'edit_commandline' # Uses C-i, but it could be whatever you want.
end

# Use with vi_mode
function fish_user_key_bindings
  set fish_key_bindings fish_vi_key_bindings
  bind . 'edit_commandline' # Pressing . while in normal/command mode will enter $EDITOR. Insert mode is unaffected.
end