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Copy a file using dc3dd and watch its progress (very nice alternative to dd)
Requires the dc3dd package - available at http://dc3dd.sourceforge.net

Leap year calculation

Find your graphics chipset
Displays only the VGA adapter/chipset being used for the graphics. In this case, it gave me the "M22" and "Mobility Radeon x300" that I needed to research a graphics issue I was having.

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Search command history on bash
Very handy and time-saving. Do a 'ctrl+ r' on command prompt. You will see a "(reverse-i-search)`':" mark. Just type any sub-string of the command you want to search(provided you have used it sometime in the same session). Keep on searching by repeatedly pressing ctrl+r. Press enter once you get the desired command string.

Catch a proccess from a user and strace it.
It sits there in a loop waiting for a proccess from that user to spawn. When it does it will attach strace to it

List of reverse DNS records for a subnet
This command uses nmap to perform reverse DNS lookups on a subnet. It produces a list of IP addresses with the corresponding PTR record for a given subnet. You can enter the subnet in CDIR notation (i.e. /24 for a Class C)). You could add "--dns-servers x.x.x.x" after the "-sL" if you need the lookups to be performed on a specific DNS server. On some installations nmap needs sudo I believe. Also I hope awk is standard on most distros.

ssh to machine behind shared NAT
Useful to get network access to a machine behind shared IP NAT. Assumes you have an accessible jump host and physical console or drac/ilo/lom etc access to run the command. Run the command on the host behind NAT then ssh connect to your jump host on port 2222. That connection to the jump host will be forwarded to the hidden machine. Note: Some older versions of ssh do not acknowledge the bind address (0.0.0.0 in the example) and will only listen on the loopback address.

Massive change of file extension (bash)
Change the file extension in batch. Useful to create output file names with same input name but distinct extension by including logic inside the loop

Capture video of a linux desktop
Proper screencast with audio using ffmpeg and x264, as per http://verb3k.wordpress.com/2010/01/26/how-to-do-proper-screencasts-on-linux/


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