Category Archive for 'Unix'

Multi-User Screen

Tuesday, October 23rd, 2007

Have you ever been jamming away on a Unix host’s command line and wish you could share your session with others? Perhaps you could do so to show someone else something you found on the system? Maybe you want that someone to type a password for you? Or perhaps you need to share the experience […]

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 […]