Mount a VM Drive on Qubes

When mounting a USB drive on Qubes v3.2, the system automatically recognizes the device, such as /dev/sdb, and its partitions, such as /dev/sdb1. They show in little rectangular notifications on the desktop. But, that doesn’t mount the filesystem. Consider mounting it on dom0 unsecure. Instead, attach the block device to a VM: Open the VM Manager … Read moreMount a VM Drive on Qubes

Show Biggest Files

Consider it a corollary of Parkinson’s Law. With large, cheap storage you shouldn’t run low on file storage any more, but as space increased, files got larger. ISO disk images. Filesystem backups. Video. Even terabyte capacity drives — thousands of gigabytes each — can run low on space. If an alert comes from the system … Read moreShow Biggest Files

Why Egrep?

The grep(1) family of search utilities are very fast. The name stands for Global Regular Expression Print because it searches globally through the files using regular expressions, AKA REs, see regex(7) for more detail, to describe what to find, and then prints its matches. Metacharacters are characters used to describe characters. Filename wildcards are simple examples of … Read moreWhy Egrep?

Get My IP

Using Existing Tools Efficient programming requires planning at both the design stage and the implementation stage. You can only improve an inefficient design so much. When prototyping with bash, work with existing tools. Typical implementation tradeoff is space against time. Using the best tools frequently improves both. Take advantage of their greatest speed and greatest … Read moreGet My IP

Hardware Queries

Several Linux utilities exist for querying and, in some cases, setting the system’s hardware. Run these utilities as root. dmidecode(8) — dnf install dmidecode DMI stands for Desktop Management Interface. This app dumps a great deal of information about the BIOS. Scrolling through the huge output is informative, but narrowing it down with certain options … Read moreHardware Queries

Collecting Server Software Versions

You manage several servers running Linux distributions. Each server’s installation may be different, due to operation purpose or due to error. How do you know which ones need attention? Need upgrades? Make your servers tell you their installed software lists. Each list shows what is installed, but comparing lists from several servers is not easy because … Read moreCollecting Server Software Versions

Better Pseudorandom Numbers

Pseudorandom number generators (PRNGs) assist simulations by giving different values tied to choices a person might make. True randomness cannot happen with deterministic software. Following in the footsteps of Donald Knuth (or directly), using the term “random” here to discuss deterministic values is easier, even if less precise than “pseudorandom”. Present a large enough set of … Read moreBetter Pseudorandom Numbers