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Comment by chopsueyar | Hacker News Reader

sudo !! runs the previous line as root, in case you forgot to type sudo

More like "sudo !!" prepends sudo to the last history entry and executes the result. It may not run as root, depending on the complexity of the shell handiwork you did, and depending on /etc/sudoers.

I really, really, really hope that the author doesn't think "sudo !!" is some special kind of magic, and that he knows "echo !!" works the same way.

Also, there are keyboards with a "Home" key? Most people just press C-a.

I'd hope that most people just hit "<esc> I sudo !!<CR>".

You said Esc-0, first.

Yeah, I first tried...

grep ".jpg"

ls | !!

...that worked too. Cool command to learn.

Thanks for the clarification, though. Original article was lacking.

Hi, I'm the author (admittedly still quite new to Unix). I did play around with the !! and realized it does a lot more. Thanks for clarifying though!

Edit: Typos

It's very powerful. There's more than just the !! for history, also. Check out http://www.catonmat.net/blog/the-definitive-guide-to-bash-co... .

Do you know where I can find a list of hotkeys along the lines of C-a? I personally created my own hotkey (shift left arrow) but learning standard ones would probably be good.

If you use bash, read the "Command Line Editing" section of "info readline".

You can also tweak the behavior of readline (for Bash and other applications) and custom make your own key combinations by editing your ~/.inputrc file. A random example from mine:

    # Insert double quotes & set cursor between them
    "\C-x\"": "\"\"\eb"
    #
    # Insert single quotes & set cursor between them
    "\C-x'": "''\eb"

See also the Bash manual:

http://www.gnu.org/software/bash/manual/bashref.html#Command...

Most shells default to emacs keybindings:

  C-a beginning of line
  C-k kill text from cursor to end of line
  C-e end of line
  M-b move cursor backwards by a word
  M-f move cursor forwards by a word
  C-w delete backwards by a word
  C-h backspace (great when real backspace doesn't work)
  C-r reverse search through command history

(C-w works in Vim(insert mode) and Emacs, but kills me when I try to type it in a browser window to delete a word... Good-bye window and/or tab)

In zsh I actually have M-w bound to the normal backspace-by-a-word and C-w bound to the vim version which will do things like count '/' as a word separator so that I can easily backspace through sections of a path rather than be required to delete the whole thing (or nothing).

Hmm, FYI most of those work in the safari reply box. I think Apple put them for all Cocoa text fields not just terminal :-)

> I think Apple put them for all Cocoa text fields not just terminal :-)

It is the NSTextField that accepts those commands. The prefix NS stands for NeXTSTEP, so the functionality existed long before Cocoa.

Yea, but you have to hit Ctrl+Option or Cmd+Option (can't remember which off the top of my head) for Meta though, instead of just Option (which is what most people bind to Meta in Terminal.app or iTerm.app).

> (C-w works in Vim(insert mode) and Emacs, but kills me when I try to type it in a browser window to delete a word... Good-bye window and/or tab)

Control-Shift-T usually solves that problem for me in Firefox.

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