Commands by arlequin (3)

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keep an eye on system load changes
helps you keep watch on the load of a system, without having to stare constantly at the terminal. The -d argument to watch highlights the difference from the last run, making it easier to note how the load is fluctuating. The sed command just strips off the information about how long the box has been up, and how many users are logged in.

Check whether laptop is running on battery or cable
The original proc file doesn't exist on my system.

Find passwords that has been stored as plain text in NetworkManager

list block devices
Shows all block devices in a tree with descruptions of what they are.

add the result of a command into vi
':r!ls -l' results in listing the files in the current directory and paste it into vi

GRUB2: set Super Mario as startup tune
I'll let Slayer handle that. Raining Blood for your pleasure.

Determine whether a CPU has 64 bit capability or not

Generate random valid mac addresses
Python Alternative

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Getting started with tcpdump
At some point you want to know what packets are flowing on your network. Use tcpdump for this. The man page is obtuse, to say the least, so here are some simple commands to get you started. -n means show IP numbers and don't try to translate them to names. -l means write a line as soon as it is ready. -i eth0 means trace the packets flowing through the first ethernet interface. src or dst w.x.y.z traces only packets going to or from IP address w.x.y.z. port 80 traces only packets for HTTP. proto udp traces only packets for UDP protocol. Once you are happy with each option combine them with 'and' 'or' 'not' to get the effects you want.


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