Part I of this Deep Dive on containers introduces the idea of kernel control groups, or cgroups, and the way you can isolate, limit and monitor selected userspace applications. Here, I dive a bit deeper and focus on the next step of process isolation—that is, through containers, and more specifically, the Linux Containers (LXC) framework.

I've recently written about using bash arrays and bash regular expressions, so here's a more useful example of using them to test IP addresses for validity.

Embedded developers working on kernels or bare-metal programs often go through several development cycles. Each time the developer modifies the code, the code has to be compiled, the ELF (Executable and Linkable Format)/kernel image has to be copied onto the SD card, and the card then has to be transferred from the PC to the development board and rebooted.

For this article, I want to look at the largest thing possible, the whole universe. At least, that's the claim made by Celestia, the software package I'm introducing here. In all seriousness though, Celestia is a very well done astronomical simulator, similar to other software packages like Stellarium. Celestia is completely open source and is licensed under the GPL.

"If we see light at the end of the tunnel, it is the light of the oncoming train" ~ Robert Lowell. Oh yes, another good quote. This post is on SSH tunneling, or as I like to call it 'Poor Man's VPN'. Contrary to the sysadmin's popular belief, SSH tunneling actually can be very valuable use for both techies and home users.

Nextcloud could be the first step toward replacing proprietary services like Dropbox and Skype. In its simplest form, the Nextcloud server is "just" a personal, free software alternative to services like Dropbox or iCloud. You can set it up so your files are always accessible via the internet, from wherever you are, and share them with your friends. However, Nextcloud can do so much more.

It's hard to write a bash script of much import without using a pipe or two. Named pipes, on the other hand, are much rarer.

iptables is the user-space tool for configuring firewall rules in the Linux kernel. It is actually a part of the larger netfilter framework. Perhaps because iptables is the most visible part of the netfilter framework, the framework is commonly referred to collectively as iptables. iptables has been the Linux firewall solution since the 2.4 kernel.