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Generate random valid mac addresses
Ruby version. Also, a perl version: $perl -e 'printf("%.2x.",rand(255))for(1..5);printf("%.2x\n",rand(255))'

View all date formats, Quick Reference Help Alias
If you have used bash for any scripting, you've used the date command alot. It's perfect for using as a way to create filename's dynamically within aliases,functions, and commands like below.. This is actually an update to my first alias, since a few commenters (below) had good observations on what was wrong with my first command. # creating a date-based ssh-key for askapache.github.com $ ssh-keygen -f ~/.ssh/`date +git-$USER@$HOSTNAME-%m-%d-%g` -C 'webmaster@askapache.com' $ # /home/gpl/.ssh/git-gplnet@askapache.github.com-04-22-10 # create a tar+gzip backup of the current directory $ tar -czf $(date +$HOME/.backups/%m-%d-%g-%R-`sed -u 's/\//#/g'

find geographical location of an ip address
a shorter version

Show your account and windows policy settings with Results of Policy msc.
Type this into windows via run and it will display to you your complete policy for windows. This includes group policy, security policy and your active directory account (min password etc).... www.fir3net.com

Display BIOS Information
read the memory from C:0000 to F:FFFF without the need auf dmidecode

Count the number of queries to a MySQL server

Create a persistent remote Proxy server through an SSH channel
Create a persistent remote Proxy server through an SSH channel.

Command to logout all the users in one command
This command logs out all users - which is way more secure to use ps -ef and "grep" to kill processes. Never ever use ps -ef piped to grep to kill something. If you ever need to ps-something use the UNIX95-directive, which makes sure you will never need "grep" together with "ps".

Create a bash script from last commands
In order to write bash-scripts, I often do the task manually to see how it works. I type ### at the start of my session. The function fetches the commands from the last occurrence of '###', excluding the function call. You could prefix this with a here-document to have a proper script-header. Delete some lines, add a few variables and a loop, and you're ready to go. This function could probably be much shorter...

List only executables installed by a debian package
I wanted to view only executables installed by a package. This seemed to work. There's got to be easier way, please share. Note: (1) Replace iptables with the package name of your interest (2) The command will trash any existing environment variable named 'lst' (3) Instead if you are interested in viewing just .ko or .so files installed by this package, then that would be easy: $ dpkg -L iptables | grep "\.[sk]o$"


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