Using GnuPG (gpg) for simple file encryption

How to use GnuPG for simple cases.

1. Install gpg, e.g.,

   sudo port install gnupg

2. Create a public/private key for yourself, e.g.,

   gpg --gen-key

   (you will have to answer some questions, I used 'knoto' as my comment
3. Encrypt a file, e.g.,

   gpg -e -r knoto myfile.foo

   (creates myfile.foo.gpg that can only be decrypted by knoto).

vim editing a remote file

Using scp:

vim scp://keith@linux.cs.wmu.edu//home/keith/my.file

You may have to re-enter your password each time you save the file. From http://tipotheday.com/2008/06/08/editing-remote-files-with-vim-and-scp

Aggregate functions in LaTeX

\usepackage{amsmath} % for underset

\newcommand{\aggregate}[2]{\underset{#2}{\operatornamewithlimits{#1\ }}}

\begin{equation}
x^{*}=\aggregate{argmax}{x\in\mathbf{\mathcal{X}}}  f(x)-g(x)
\label{foo.eq}
\end{equation}

Looks like:

Setting up ssh/http port mapping on a Mac using Airport (Extreme)

1. Find your computer's MAC address
   • Airport utility
   • Advanced section
   • Logging & statistics tab
   • Click on "Logs & statistics" button
   • DHCP clients section
2. Ensure that DHCP IP address stays the same.
   • Airport utility
   • Internet section
   • DHCP
   • Add a DHCP reservation
     • Description: e.g., Norple@10.0.1.2
     • Reserve by MAC (not client—it's not working for me)
     • I used 10.0.1.2, a fine IP address indeed
3. Set up port services
   • Airport utility
   • Advanced
   • Port Mapping
   • Add:
     1. SSH (choose nonstandard public port, like 2319, private can be 22)
     2. Person web sharing
     3. Others...?
4. Update Airport so that it shuts down and restarts
5. Set up web and file sharing on your computer
   • System preferences
   • Sharing
   • Check remote login, web sharing, whatever you want.

Combining Multiple PDF files into one

gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf source1.pdf source2.pdf source3.pdf

Source:http://hints.macworld.com/article.php?story=2003083122212228.

Back-up DVDs from a MacOS command line

How to backup DVDs (this approach will not overcome copy protection--because of the ripping process).

Prereq:

Install dvdbackup from http://dvdbackup.sourceforge.net. Note that this requires libraries (i) libdvdread and (possibly, ii) libdvdcss. Download and install the libraries, then dvdbackup (all are ./configure,make,sudo make install). Additional note: I installed libdvdread via mac ports, but dvdbackup failed to configure because it required a different version. I then downloaded and installed version 0.9.7 separately, then ./configure worked (I also downloaded and installed libdvdcss--not sure if that matters.)

To backup a DVD:

1.  dvdbackup -v -i /dev/disk1 -n NAME -M 

   where /dev/disk1 should be replaced with the device currently associated with the inserted disc, and NAME is whatever name you want to assign to the project. It turns out, the -n option is necessary. Without more options, dvdbackup creates a similarly-named directory and writes the files there (the -v option is just for verbosity--use dvdbackup --help)

2.  hdiutil makehybrid -udf -o NAME.iso path-to-FOLDER 

   where NAME is again up to you, but path-to-FOLDER must contain the VIDEO_TS directory created by dvdbackup (it must not be the VIDEO_TS directory itself). Typically, this will be the directory created by dvdbackup.
3. Burn the image with

    hdiutil burn NAME.iso 

   This, apparently, finds your DVD device, writes and ejects it.

Good luck.

auto-indent an entire source code file in VI (vim, gvim)

gg=G

=, the indent command can take motions. So, gg to get the start of the file, = to indent, G to the end of the file, gg=G.

http://stackoverflow.com/questions/506075/how-do-i-fix-the-indentation-of-an-entire-file-in-vi