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Be notified about overheating of your CPU and/or motherboard
You'll be notified if your core 1 temperature exceeds 50 degrees, you can change the monitored device by editing the "Core 1" or change the critical temperature by editing the "-gt 50" part. Note: you must have lm-sensors installed and configured in order to get this command working.

Live stream a remote desktop over ssh using only ffmpeg
Play with the framerate option '-r' to scale back bandwidth usage. The '-s' option is the captured screan area, not the rescaled size. If you want to rescale add a second '-s' option after '-i :0'. Rescaling smaller will also decrease bandwidth.

Get the list of root nameservers for a given TLD

show each new entry in system messages as a popup
It willl popup a message for each new entry in /var/log/messages found on the notify-send howto page on ubuntuforums.org. Posted here only because it is one of the favourites of mine.

April Fools' Day Prank
Add this to a fiend's .bashrc. PROMPT_COMMAND will run just before a prompt is drawn. RANDOM will be between 0 and 32768; in this case, it'll run about 1/10th of the time. \033 is the escape character. I'll call it \e for short. \e7 -- save cursor position. \e[%d;%dH -- move cursor to absolute position \e[4%dm \e[m -- draw a random color at that point \e8 -- restore position.

Check SSH public and private keys matching
Tested in bash4

Using bash inline
There are two ways to use "here documents" with bash to fill stdin: The following example shows use with the "bc" command. a) Using a delimiter at the end of data: $ less-than less-than eeooff bc > k=1024 > m=k*k > g=k*m > g > eeooff 1073741824 b) using the "inline" verion with three less-than symbols: $ less-than less-than less-than "k=1024; m=k*k; g=k*m; g" bc 1073741824 One nice advantage of using the triple less-than version is that the command can easily be recalled from command line history and re-executed. PS: in this "description", I had to use the name "less-than" to represent the less-than symbol because the commandlinefu input text box seems to eat up the real less-than symbols. Odd.

Trace a DNS query from root to the authoritive servers.
Simple command to trace a DNS query from the root all the way to the authoritative servers.

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


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