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Add a DNS server on the fly
Since systemd-resolved was implemented, add a DNS server have become weirder and harder than before. With this command, you can add a DNS server on-the-fly tied to an specific interface

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

use xxd to create the wake on lan magicpacket and write to pcap file
just set macdst to the mac address of the system you wish to wake up, the macsrc is optional but helps use tcpreplay to broadcast or wireshark to view

Lookup hostname for IP address

pretend to be busy in office to enjoy a cup of coffee
The first parameter after timeout is the key parameter; number of seconds to wait. With a 6 you have 600 seconds for your coffee break (10min).

peak amount of memory occupied by any process with "FOO" in its name
Show the maximum amount of memory that was needed by a process at any time. My use case: Having a long-running computation job on $BIG_COMPUTER and judging whether it will also run on $SMALL_COMPUTER.   http://man7.org/linux/man-pages/man5/proc.5.html VmHWM: Peak resident set size ("high water mark")

Anti DDOS
Takes IP from web logs and pipes to iptables, use grep to white list IPs.. use if a particular file is getting requested by many different addresses. Sure, its already down pipe and you bandwidth may suffer but that isnt the concern. This one liner saved me from all the traffic hitting the server a second time, reconfigure your system so your system will work like blog-post-1.php or the similar so legitimate users can continue working while the botnet kills itself.

Display Spinner while waiting for some process to finish
alternatively, run the spinner for 5 seconds: timeout 5 bash -c 'spinner=( Ooooo oOooo ooOoo oooOo ooooO oooOo ooOoo oOooo); while true; do for i in ${spinner[@]}; do for j in seq 0 ${#i}; do echo -en "\b\b"; done; echo -ne "${i}"; sleep 0.2; done; done'

Simple addicting bash game.
Really bored during class so I made this... Basically, you hold period (or whatever) and hit enter after a second and you need to make the next line of periods the same length as the previous line... My record was 5 lines of the same length. It's best if you do it one handed with your pointer on period and ring on enter.

Delicious search with human readable output
You can install filterous with $ sudo apt-get install libxslt1-dev; sudo easy_install -U filterous


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