Kevin Kleinfelter's blog


I don't know where this came from, but it is helpful in dealing with tags on Mac OS X.

Why I Don't Use Tasker

Tasker is a nifty app for Android. (There's nothing like it for iPhone/iOS because of sandbox limitations.) It allows all sorts of "when this happens do that". e.g. When I'm connected to WiFi but it is not my home WiFi, start VPN.

It is complicated to learn, but wonderfully powerful.

Build a UDP VPN Config File from TCP Config

I'd like to have a UDP instance too. As I've mentioned, in theory, running a VPN over UDP should work better than running it over TCP. When you have TCP layered over TCP, if you run into network latency, you can have both layers retransmitting, and the upper layer can exacerbate the latency of the lower layer with the extra traffic.

Note: On my Pi, UDP performs MUCH worse than TCP. I haven't figured out why.

cd /etc/openvpn
sudo cp server1.conf server2.conf

Edit server2.conf and:

Practice Revoking a VPN Certificate

Sooner or later, someone is going to lose a laptop or a cell phone and you'll need to revoke his/her certificate so that the thief can't use your VPN. When you put a .ovpn file on an client, be certain that client has a good password (e.g. a good screen-lock PIN on your cell phone or a strong Windows password on your Windows PC - with a short timeout on the lock-when-idle.)

On the machine where you built your keys:

Open Your Firewall on Your Pi VPN

You can't connect to a VPN on your Pi if your firewall blocks access. Your Pi came with a built-in firewall. We need to open the necessary ports on your Pi.

  • Create a script named /etc/openvpn/ Make it contain this:

Grant Only Dad Access to the Home LAN

Maybe you want to access your home LAN while out, but you don't want your kid's phone to access your LAN. If he loses that phone and it isn't passworded, someone could (theoretically) find the phone, pull the certificate off, access your VPN, and then access files on your home LAN.

Use a Raspberry Pi for a VPN Server

OK, coach. I think I'd like to run my own VPN, but I'm on the economy plan. I can't afford to buy a new computer.

The Raspberry Pi is nominally $35. That will buy you a multi-core CPU, a gig of RAM, an Ethernet port, etc. What it doesn't include is

Combine Multiple Images to a Single PDF With Preview on Mac OS X

I wanted to combine multiple TIFF images into a single PDF on Mac OS X. Here's how:

  • Start Preview.
  • File >> Open >> open all the files you want, using CMD-click to select.
  • Drag the thumbnails into the desired order
  • File >> Print >> PDF >> Save as PDF

Convert to PDF - OS X Command Line (Terminal)

To print to PDF (convert) most SINGLE PAGE files in OS X:

cupsfilter foo_name_here > foo.pdf 2>/dev/null

If you run this with a mult-page TIF as input, the output will truncate everything after the first page.

Create a Mac OS X Finder Service

Here are some notes on creating a Service for Mac OS X Finder. This will add an item to the Finder Services menu (available under the Finder menu and also by right-clicking on a file in Finder). This particular service will convert a simple .html file into a .rtf.

The basic commands you want to run on the file are:


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