Hi HN! I'm the post author, and if I would've known someone was submitting this to HN, I would've researched a bit more! This was more for my reference. Thanks for all the tips though, got to learn a lot from this thread..
!$ takes the last argument from the previous command, instead of the whole thing.
chmod 664 site/* - changes the permissions for all the files in the site directory. * is a wildcard in bash for specifying directories.
Another useful feature of bash is brace expansion:
mv site{,-old} => mv site site-old
The brace expansion expands the argument with the values in a comma separated list: college pic_00{1,4,3}.jpeg college.jpeg yields pic_001 pic_004, pic_003
* is a wildcard for everything in the directory including files and directories.
so the chmod will remove the execute permission from directories also.
The biggest shell-related revelation for me recently was that ~ is a special character in SSH. If you have an SSH session that's hanging and ctrl-C / ctrl-D isn't responding, try typing "~." (without the quotes).
The ~ needs to follow a newline. So I usually make sure to hit <Enter> explicitly before hitting "~." so that I don't have to repeat the sequence if it doesn't work. It would still work without hitting <Enter> explicitly if the last thing that you typed to the console was <Enter> though.
It's usually because I've accidentally fumbled ctrl-s which means 'play dead'. Why that's important enough to take a two-key home row shortcut, I don't know. The cure is to press ctrl-q. Same wonder about the cure.
I can't argue for it taking such a prime spot on the keyboard, but I used c-s/c-q every day to freeze scrolling output that I want to look at. Your terminal scrollback will still work during the pause.
It's pretty much the same number of keystrokes aside from having to hold down the Ctrl key. However, I can now go back in my history and run the command again. Also, if I mistyped something, I can easily hit Ctrl-P and fix it without having to retype sudo.
!! (bang-bang) is expanded by the shell before its committed to your history (at least in bash), so if you hit ctrl+p, you'll get the full sudo command for running/modifying later.
In zsh, !! is expanded by the shell, but leaves the expanded command at the terminal, waiting for you to execute it. Most of the time this means I have to hit enter twice to run the command, but it's convenient when I want to explain to someone what !! is useful for.
I don't have that enabled but zsh also expands bang constructs with tab. So any commands I want to double check, or if I am demonstrating to someone, I just hit tab. Also handy for expressions like !-2:3 where if I messed up I can just hit "undo" and then retry.
On a related note, when you want to insert something at the start of a line in a shell, rather than hitting home, I find ctrl-a to be very useful. Especially on a macbook, where cmd-left doesn't work in a shell (for some reason) and there is no home key.
This often works in unexpected places. For example: testing it right now, I can click the address bar on google chrome, hit ctrl-a (not cmd-a) and the caret is at the start of the url.
ctrl-a (beginning of line), ctrl-e (end of line), ctrl-k (kill/copy line), ctrl-y (yank/paste line) are standard emacs keybindings. On OS X, they work in any standard NS text field as well. More at http://www.hcs.harvard.edu/~jrus/site/cocoa-text.html
BTW, when using screen, ctrl-a is its default action key, so use ctrl-a ctrl-a to send a real ctrl-a, or change the default screen action key in your .screenrc.
> BTW, when using screen, ctrl-a is its default action key
This ends up annoying me on a regular basis. Let's say I want to make a directory and then go to it. I would type:
mkdir foo<Ctrl-p><Ctrl-a><Alt-d>cd<Enter>
Except when using screen, <Ctrl-a><Alt-d> (really just <Ctrl-a>d) detaches the session. It's solved easily enough ("screen -r"), but it always yanks me out of my groove.
I prefer to bind it to ` with `` to send a real `. It makes it really easy to flip back and forth between two screen windows since last-window is now:
`q
Now I don't even have to use Ctrl. This takes a little getting used to, but I prefer to use $() instead of `` for shell scripts (I use bash/zsh) so I don't make use of ` that often.
I do have bindings on F11 and F12 to toggle the escape character between ` and C-o. (Just in case I need to paste something into a terminal with ` characters.)
(Note: This whole setup is ripped off from some StackOverflow or HN post.)
Another one to add to the list, when working in the shell, is ctrl-u. This sort of does the opposite of ctrl-k and clears everything from your cursor to the start of the line. I use it when I recursive-search then change my mind, or when I screw up a password when ssh'ing.
It's my understanding that these keycombo's are originally from the readline library. Other programs that have these combo's available are irrsi and bash but I love to know more!
Your MacBook does have a home key, it's just not labelled any more. fn+left arrow is home, and end is the obvious counterpart. fn+up/down are page up/down too.
I use ctrl-a and ctrl-e too, but sometimes you're using remote desktop (or synergy) with a Windows machine...
Something like that. Having done it once, up-arrow into your history to the wget, hit "Ctrl-O" and it'll execute the wget, and now the java command is ready. You can just keep cycling through with Ctrl-O, since executing the command puts it in the end of your history. If you need to update the command, the fix is available for later. One of those "use it so that you remember, 'cause boy-howdy it's handy"
I never do this, I prefer to recall the actual command to see if it is correct, especially for sudo.
The reason is that you might not execute the command you were thinking of. The HISTIGNORE variable contains a quasi-regex of commands that are not stored in history. If the previous command matched that regex, you will end up executing the previous command to that one, not what you wanted at all.
Why use HISTIGNORE?. So that things like 'exit' or common commands like 'ls' don't pollute your history file.
I've really enjoyed Ctrl+a and Ctrl+e recently to move between the beginning and end of the command prompt - it's really a lot more useful than I initially thought.
From what I've seen (and I may be wrong here), I think the post that enters the front page stays on the top just for a short amount of time, before gradually settling down on a position determined by the time it's been there, the votes it's got and flags. The post will keep sliding down with time.
Edited: Clarifying.
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.
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.
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).
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).
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"
