Sam's Homepage

This is Sam's (a.k.a. Peabody's) homepage. Send me mail at peabodyenator AT gmail.com. I'm interested in meeting new people, especially those who come by here. I'm surprised anyone would bother. I'll especially love you if you find a grammar or spelling misake mistake (and tell me about it).

What's Here?

Stuff. I mostly only place pictures, musings, and pointless programs I write. I tire of maintaining links since I write all my html in Emacs. Sorry about the long page.

What's New?

I got straight A's again at UC Davis (spring quarter 2008)!

Old Stuff

I finally found a really good article on configuring Emacs PSGML mode with document type definitions. PSGML mode is what I use to edit this homepage.

Other Pages

I gruadually add other things when I feel like it. I have regular expressions page an editor wars page and a netpbm page.

Sam's Long Random List of Unix Notes

I've used Unicies of various kinds and my trouble is my memory's spotty. So when I come across something in the Unix world I like, 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.

Shell Magic

Rename the extension on a group of files -- ls *.ext | while read item; do mv "$item" `echo '$item' | sed 's/\.ext/.newext/'`; done

Downcase all the filenames in a folder -- ls * | while read item; do mv $item `echo "$item" | sed 's/.*/\L&\E/'`; done

Subversion

I've been trying to move anything I type to version control. It hasn't happened yet though (I'm lazy).

• Creating a repository. -- svnadmin create <folder>
• Importing -- svn import <files> <url> -m 'message'
• Checkout -- svn co <url>
• Commit -- svn ci <files> -m 'message'
• Setting RCS keywords -- svn propset svn:keywords <keywords> <files>

ssh,scp,ssh-keygen

• 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.
• ssh-keygen -t rsa then scp ~/.ssh/id_rsa.pub to the host and cat it onto ~/.ssh/authorized_keys. Be sure the directory permission is 700!
• ssh -L 5901:localhost:5901 <host> -- This will tunnel vnc via ssh. Very worthwhile.

Rsync

• The follow is pretty much how I always use rsync to update conf files between machines: rsync -r -tv -e ssh localdir1 localdir2 ... localdirn user@host:.. Turns on recursion, preservation of timestamps, verbose output, and use ssh.

Find

Find is quite possibly the most important utility in any Unix admin's toolbox. I've listed some examples below. Read the man page for more information.

Notice I've appended | tee ~/find.log to the end of each command below. It isn't necessary, but I really prefer to do this so that my search results get saved to a file I can work with later.

In fact, a fun way to work with find is to create a shell function so that this always happens:

function find {
  /usr/bin/find "$@" | /usr/bin/tee ~/find.log
}

One last point...because of fuse, my home folder has recently become home to network and encrypted filesystems. Making -xdev the first option of the search expression avoids searching these filesystems.

• Find all files modified exactly 24-hours ago in your home folder: find ~/ -mtime 1 | tee ~/find.log
• Find all files modified within the last 24-hours in your home folder: find ~/ -mtime -1 | tee ~/find.log
• Find all files modified within the last 5 hours in your home folder: find ~/ -mmin -$((60 * 5)) | tee ~/find.log
• Find all regular files which have any of their execute bits set: find ~/ -perm -ugo=x -type f | tee ~/find.log
• Find all directories missing any of their execute bits: find ~/ -perm +ugo=x -type d | tee ~/find.log
• Find all jpeg files regardless of case: find ~/ -regex '.*\.[jJ][pP][eE]*[gG]' | tee ~/find.log
• Find all broken symbolic links: find -L ~/ -type l
• Prune (ignore) part of a directory tree: find ~/ -path ~/'folder*' -prune -o (actual search here)
• Find all backup files older than two weeks and delete them: find ~/ -name '*~' -type f -mtime +14 -exec rm {} \; | tee ~/clear.log
• Only search the current folder: find ~/ -maxdepth 1 (search goes here) | tee ~/find.log

Wget

• wget --no-host-directories/-nH I think this is an annoying default, but it does help keep things a bit safer and accounted for.
• 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.

Linux LVM

In a rescue system, to access lvm drives try vgscan, vgchange -ay, vgmknodes. mount drives before the chroot and then chroot target. You may have to also mount -t proc proc /proc to make some utils happy.

dpkg

I used to run Fedora, but I've switched to Ubuntu. Now everything uses dpkg so this is here to remind me how to investigate packages.

• List Package Contents -- dpkg -L <package name>
• Show Package Description -- dpkg -p <package name>
• Show All Installed Packages -- dpkg --list
• Show Which Package 'filepath' Belongs To -- dpkg -S filepath

Vim

This section coming soon. I've been playing around with Vim lately. I'll be adding a section here shortly.

Emacs

I use GNU emacs where I can get away with it. It's hard sometimes, it often won't come on small bootable Linux systems of which I find myself in from time to time, in which case it's often Nano or vi (yes, I have to use sometimes). 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 I can't live without and can't often remember. I usually to spend time tweaking GNU emacs when I load it up for the first time on a system. I've set this place up as my cheat sheet.

I can't emphasis enough how useful the Emacs Wiki is. It's invaluable.

• When in doubt, launch emacs with "-q". This starts a clean Emacs that ignores your startup file. Use --no-site to run emacs without custom site-wide configurations
• 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 can 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! Scratch that. I've grown found of the default way backup files are kept.
• M-x normal-erase-is-backspace to fix backspace problems 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! CVS Emacs (which is what I use now) only needs (desktop-save-mode). The previous advice is still useful if you're stuck with a previous version of Emacs.
• (setq dired-recursive-copies t) and (setq dired-recursive-deletes t) to copy and delete recursively in Dired (Emacs' DIRectory EDitor). Admittedly, I don't really use this.
• There are several useful rings in Emacs. Sometimes I 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 search ring preserves your previous searches and can save lots of typing. Use M-p and M-n to cycle through previous searches. There is a seperate ring for every type of search. 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>. Using the mark ring in conjunction of searching is a great way to zip around a file quickly. Makes me wonder why we even need mice.
• 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. CVS Emacs has expanding macro functionality. There is now a macro ring that preserves the last few macros, and start-kbd-macro and end-kbd-macro have bindings to F2 and F3. 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 expressions; 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: * % <type your regular expression with groupings> RET new name with groupings. If you don't know regular expressions yet, this is a very good reason why you should learn them ;).
• 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.
• Any character can be typed in Emacs 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/"

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Games

That Block Game

A simple Tetris clone I wrote in Pygame. For free as in beer and in freedom under the GPL v2.

• Source
• Windows Executable (need help, don't have a Windows Machine :()
• Macintosh Executable

Hangman

What computer isn't complete without a game of hangman? Written in C++, uses getopt.h, so it might not compile on windows.

hangman.cpp

My speed tests for my comcast connection. Not bad if I do say so myself.