Archive for September, 2007

Answers to the Redirection Puzzle

Thursday, September 27th, 2007

This post discusses answers to the Redirection Puzzle. Do not read on if you do not want to see or discuss answers (yet).

Redirection Puzzle

Thursday, September 27th, 2007

Today’s entry here at is a little Unix puzzle for everyone to work. I came up with this seven years ago when I was first reading about the Plan 9 shell, rc. Plan 9’s shell has a nifty little syntax for connecting a pipe from an arbitrary file descriptor of one process to any […]

Mind the Arguments

Saturday, September 22nd, 2007

How command line arguments are processed in Unix is important to know when scripting. That which should be a simple script is often troublesome to debug if the arguments to some of the commands get mangled unexpectedly. To help understand what ends up being sent as command line arguments to a command, we can use […]

Scrutinizing SSH

Tuesday, September 18th, 2007

In my previous post titled Bolting on Security, I mentioned that port 22 is generally not scrutinized as much as 445 when being allowed through a firewall. Obviously the situation varies from incident to incident, but I wanted to say that port 22 really should be looked at more closely. All is not always roses […]

Bolting on Security

Friday, September 14th, 2007

To build security in your project, you need to make it a consideration from the start. Bolting it on afterward is always a recipe for disaster, and unless you start over with a complete application rewrite you are likely to fail to secure your application in some subtle manner or another. If you are in […]