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Create a video screencast (capture screen) of screen portion, with audio (the audio you hear, not your mic)
Errors in output don't matter. Stop recording: ctrl-c. Result playable with Flash too. IMPORTANT: Find a Pulse Audio device to capture from: pactl list | grep -A2 'Source #' | grep 'Name: ' | cut -d" " -f2

dump 1KB of data from ram to file

Tail -f at your own pace
The -s option allows you to specify the update interval

Send data securly over the net.
Using OpenSSL we can encrypt any input we wish and then use Netcat to create a socket which can be connected to from an externally source (even using a Web Browser)

Scan Network for Rogue APs.
I've used this scan to sucessfully find many rogue APs on a very, very large network.

beep when a server goes offline
pings a server once per second, and beeps when the server is unreachable. Basically the opposite of: $ ping -a server-or-ip.com which would beep when a server IS reachable. You could also substitute beep with any command, which makes this a powerful alternative to ping -a: $ while true; do [ "$(ping -c1W1w1 server-or-ip.com 2>/dev/null | awk '/received/ {print $4}')" = 1 ] && date || echo 'server is down!'; sleep 1; done which would output the date and time every sec until the ping failed, in which case it would echo. Notes: Requires beep package. May need to run as root (beep uses the system speaker) Tested on Ubuntu which doesn't have beep out of the box... $ sudo apt-get install beep

Execute a command without saving it in the history
Prepending one or more spaces to your command won't be saved in history. Useful for pr0n or passwords on the commandline. Tested on BASH.

randomize hostname and mac address, force dhcp renew. (for anonymous networking)
this string of commands will release your dhcp address, change your mac address, generate a new random hostname and then get a new dhcp lease.

Backticks are evil
This is a simple example of using proper command nesting using $() over ``. There are a number of advantages of $() over backticks. First, they can be easily nested without escapes: $ program1 $(program2 $(program3 $(program4))) versus $ program1 `program2 \`program3 \`program4\`\`` Second, they're easier to read, then trying to decipher the difference between the backtick and the singlequote: `'. The only drawback $() suffers from is lack of total portability. If your script must be portable to the archaic Bourne shell, or old versions of the C-shell or Korn shell, then backticks are appropriate, otherwise, we should all get into the habit of $(). Your future script maintainers will thank you for producing cleaner code.


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