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Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Measure, explain and minimize a computer's electrical power consumption
Run this command as root to get enough stats. It works on AMD and Intel machines, including desktops. If ran on a laptop it'll give you suggestions on extending your battery life. You'll need to install PowerTOP if you don't have, via 'apt-get install powertop', etc. To grep the output use: sudo powertop -d | grep ... The many command suggestions PowerTOP gives you alone will increase your command-line fu!

Show exit status of all portions of a piped command eg. ls |this_doesn't_exist |wc

Calculating series with awk: add numbers from 1 to 100
"seq 100" outputs 1,2,..,100, separated by newlines. awk adds them up and displays the sum. "seq 1 2 11" outputs 1,3,..,11. Variations: 1+3+...+(2n-1) = n^2 $ seq 1 2 19 | awk '{sum+=$1} END {print sum}' # displays 100 1/2 + 1/4 + ... = 1 $ seq 10 | awk '{sum+=1/(2**$1)} END {print sum}' # displays 0.999023

Smiley Face Bash Prompt
If your last command was a dud, your bash prompt will be angry at you. Otherwise it's happy. Soon you will crave its constant approval and your linux skills will improve simply to avoid low self-esteem.

Disable WoL on eth0

Progress bar for MySQL import
Print out the progress of MySQL import using the pv command. Updates every second.

Load average + API google chart
limite = threshold

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

Convert the contents of a directory listing into a colon-separated environment variable
Useful for making a CLASSPATH out of a list of JAR files, for example. Also: export CLASSPATH=.:$(find ./lib -name '*.jar' -printf '%p:')


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