Tim's Computer Science Blog

Sometimes there are good old things that we just can't get away from. Something about the continued functionality inspite of the "newer better" hype cycles in technology. I digress though, so onto the meat of this post. There is an issue that has plagued an old laptop of mine for a while. It happened when I would change the HardDrive in the machine. (Think cycling through Windows 7, 8, 10, Ubuntu, Fedora, Debian, etc) Each time the HD was switched up the bootloader would cease to work. Worse yet a fresh install wouldn't work. DunDunDun! Hardware Issues! Turns out the nvram was having issues. Luckily Linux has this handy command line tool efibootmgr  to save the day. Grab a Live Cd/USB and Extra entries can be deleted by command like    sudo efibootmgr -b entry_in_nvram -B    . You might also want to remove excessive dump files using a command such as    sudo rm /sys/firmware/efi/efivars/dump-*   If needed check your OS for how to regenerate y...

Here is a slide by slide guide on how to setup and create virtual machines, and even network them together. This is really useful to know about if you want to simulate setting up servers, networks, and various technologies and then test them. For those who are into cyber security you can safely practice your skills! You don't even need to spend money on a bunch of additional hardware!

 I recently came across a post talking about how Linux is used as a barrier to keep people out of tech. Huh? Wasn't part of GNU Linux founded on the idea the code should be free, as in freedom? (not free as in beer) Anyone can get it, freely, and use it freely, and change it how they like freely. All this free access is supposed to help people who might not otherwise have access to pay, or be controlled by those own own the rights to said software. (among other ideals within the free software movements) It worked for me, and my bootable cd of knoppix when I first got started. Choose an operating system you are comfortable with, that you like, that fits your needs. Please realize that for some of us, Linux broke down the barriers. It's not an IT gatekeeper to learn something new. *I should probably avoid potentially controversial topics like this... It's just that I care about something that gave me opportunity.

I recently made a quick draft of useful Linux bash commands for a group getting introduced to capture the flag events.  This is what I consider the basics, and should be enough to get through most easy to medium level puzzles. Good luck and happy hacking. (At Some point I'll link a PDF, or add some links here) Useful Linux Commands! You may find this reference document useful: Document  (I've copied the contents below as well) Table of Contents: Intro Quick Command Descriptions Command Examples & Syntax Intro: This is a mixture of the shell (command line tool) and some common linux system programs. To use these commands you can either run Linux on your computer or use a virtual machine with Linux installed on it. The shell that we are using is called Bash (Bourne again SHell) For Windows: 1.       Cygwin (A bash shell for windows I highly recommend) 2.       WSL (Windows subsystem for linux) ...