OpenSSH 4.2 and above now have true vpn functionality using tun(4) devices. Unfortunately this functionality has not yet made it into the portable version (not in Linux at least). Don't panic though, you don't need tun to use SSH as a VPN 
 * OpenSSH 4.3p1 added support for FreeBSD, NetBSD and Linux tun devices.

Apache (NCSA) Visitor statistics

I've been looking through some old files and I found this log analysis script kicking around. It's really simple and outputs the total hits and unique hits (visitors) per day as read from a NCSA format log file. Thought I would post it here for posterity.
This really is first exercise in "bash for dummies" type stuff though ;p 
Not that I have that book or even know if it exists? 


GPGSesame is a perl script that collects and verifies Open PGP signed / encrypted mail and allows access through a Linux Netfilter firewall. This enables you to remotely open holes in your iptables by simply sending a GPG email to authenticate yourself. The version here opens acess to the SSH port, but you're free to modify the script if you want to change that.

Performance Monitoring script

This is a script which can collect perfomance statistics at desired intervals and convert the output into a CSV report which you can then import into a spreadsheet or database for further analysis. It uses standard unix utilities (iostat, vmstat, netstat, uptime) and has been tested on Linux and Solaris systems.

Apache mod_proxy statistics

This is a little script I wrote that uses awk to generate information on Apache mod_proxy performance. The script is called and it takes in a list of log files to process. 
For each log it tells you how many requests were served along with the real numbers and percentages of those that were Hits, Misses or Un-cacheable. It breaks each one down by HTTP return code.

KITT Sillyness

The Knight Industries Two Thousand on your keyboard! Remember KnightRider? This evolved during a wildly off-topic discussion on slashdot. Add these two aliases to your .bashrc and then run KITT to make your num,caps,scoll lock LEDs behave like the panel in KITTs bonnet.
 alias setleds='setleds -L < /dev/tty1'

Gaming sites

Linux Gaming sites you need to know about.
    1. linuX Gamers
    2. Linux Games
    3. Happy Penguin

DDNS Firewall Holes

One method I've used for accessing my home box from the interweb is to use a dynamic DNS account. I have a script that is run from cron that does a lookup on a certain hostname and updates an iptables chain whenever the IP changes. 
I don't need to leave SSH open, I just carry the username/password for the ddns account and update it whenever I need access from somewhere. Within a few minutes a hole is opened through the firewall and I can log in.