Sam's Long Random List of Unix Notes

Unix is one ugly duckling. It's also awesome. I don't care what anyone says, maybe it isn't for everyone, but it's hard not to admire something about it. I've used Unicies of various kinds and I love 'em all. Trouble is my memory's spotty as hell. So when I come across something in the Unix world I just love, I try and jot it down here. I also jot down other notes and craziness regarding things less Unix centric, such as Python notes or Firefox notes.

Organization's not my strong point. Good luck readin' this. I hope you find it useful.

Emacs

I use GNU emacs where I can get away with it (It's damn hard sometimes, it often won't come on small boot-able Linux systems of which I surprisingly find myself in from time to time, in which case it's often Nano or *GASP* a vi-flavor-of-the-month). My problem is I often forget the emacs-lisp incantations I like to keep in my .emacs file, so here's my safe, simple, emacs file in case I need it, as well as my Elisp libraries I use, and here's a list of common emacs lisp settings and lore I can't live without and can't often remember :-D. I often find I need to spend time tweaking gnu emacs when I load it up for the first time on a system, so I've set this place up as my cheat sheet, and emacs resource page.

I can't emphasis enough how useful the Emacs Wiki is to us Emacs users. It's invaluable and a far cry better than these loose notes.

WHEN IN DOUBT, LAUNCH MR. EMACS WITH "-q" AND COMPLETELY DISREGARD A TERRIBLE BROKEN STARTUP FILE, USE --no-site TO RUN EMACS WITHOUT CUSTOM SITE-WIDE CONFIGURATIONS
Remember, for Emacs novices, you can use the menu, even in a terminal. F10 will get you to the menu, but if the terminal emulator you're using doesn't let you send f10, you push ESC ` instead. There's lots of useful functions you can access easily from the menu, and if one of them happens to be bound to a keyboard shortcut, it'll tell you what it is after using it.
(setq backup-directory-alist '(("." . "~/.my_backups"))) Helps keep those backup files from cluttering your directories. Make sure the directory "~/.my_backups" exists!
M-x normal-erase-is-backspace to fix the inevitable backspace problems one faces when jumping between Mac PC environments and terminal emulators.
Saving editing sessions is incredibly useful with(desktop-load-default) (desktop-read)in the .emacs file. Don't forget to save your session the first time with M-x desktop-save and don't forget to start Emacs in the same directory as before!
(setq dired-recursive-copies t) and (setq dired-recursive-deletes t) to copy and delete recursively in Dired (Emacs' DIRectory EDitor).
Rings are incredible things in Emacs, never forget about them! There's the kill ring, the search ring, and the mark ring. To cycle through the kill ring C-y then M-y to cycle through the last few things killed in the current buffer. They're always there until the kill ring runs out of room, and it'll keep looping, so it's a great robust way to save text. The mark ring is perhaps the most under used and under appreciated feature of Emacs in my opinion. You can set the mark with C-<SPC> which will also allow you to set the region by moving the point, but you can also move back to the mark and cycle through all your recent marks in the current buffer with C-u C-<SPC>
Macros, Macros, and more Macros. Never forget about Macros. C-x ( to start one, and C-x ) to finish it off. C-x e to execute it. C-u C-x ( to execute and add more to it. M-x name-last-kbd-macro to name it for later. C-x C-k Edit a previously defined keyboard macro, and M-x apply-macro-to-region-lines to run it over your highlighted region. There's an elisp package "kmacro.el" that provides even more macro goodness including a Macro ring. And don't forget M-x insert-kbd-macro, I have a tendency to write useful macros out to a hidden file in the working directory of a project called ".macros.el" so I can load 'em later. If you want to make a named keyboard macro the current keyboard macro, just define another macro and call the macro via M-x
Dired is awesome once you get used to it. I've heard that people who despise Emacs will use it. It's the ultimate tool to clean up Emacs' poo (backup files, auto-save files, etc.); search the contents of each file in a directory structure for a regular expression; copy, compress and make backups; load and compile elisp libraries; and batch rename files. Pop into a directory with C-x C-f. Use this awesome sequence of commands to rename a series of files based on regular expressions:
Emacs is the ultimate BBEdit for unix when it comes to converting ascii formats and character sets. C-x RET f let's you change what format the text you're working on is for writing. A super quick way to convert Mac->PC->Unix Ascii.
Man can type any character in the Emacs world by quoting it with C-q. The rest is up to your terminal emulation software and its ability to send that character..
Info-directory-list is a useful variable for maintaining locally installed Info documentation. If you don't have root on a machine, it's impossible to install Info documentation site wide so you'll need to use this variable. However, the better mechanism is to set the INFOPATH environment variable. This can be tricky, because you need to explicitly point INFOPATH to site-wide directories as well. Mine looks like this on the SDF: INFOPATH="~/.elisp/info/":"/usr/pkg/info/":"/usr/share/info/"

Bash

Sed, Awk, tr

I don't normally touch these tools, but here's a few invaluble one-liners that have gotten me out of more than a few jams.

Ispell/Aspell

ssh,scp

ssh -L <localport>:<tunneled remote host>:<port on remote host> user@host -- The magical incantation for local port forwarding.
ssh -R <remoteport>:<tunneled local host>:<port on local host> user@host -- Basically the opposite of -L, a great way to get into a machine behind a firewall if you have local access. Just ssh out from it to your home computer, or a computer with ssh access. Leave the connection open and then tunnel right back in.
scp <localfile>

Rsync

The follow is pretty much how I always use rsync to update conf files between machines: rsync -r -tv --delete-after -e ssh localdir1 localdir2 ... localdirn user@host:.. Turns on recursion, preservation of timestamps, verbose output, delete-files not present on the local machine, and use ssh.

Wget

wget --no-host-directories/-nH I think this is an annoying default, but I guess it aint all bad, it does help keep things a bit safer and accounted for. None the less I like to get rid of 'em quick like. In fact I often alias wget='wget -nH' in Bash.
wget -m for mirror mode. If I'm pulling down more than one thing off the web I generally use this.
You almost always want to call wget with -np which stands for No Parent and means that you don't recurse higher than the first directory fed to wget. Trust me on this one, it can be very bad.