today's howtos
-
How to install GRV (Git Repository Viewer) on Ubuntu 22.04
Hello, friends. In this post, you will learn how to install GRV (Git Repository Viewer) on Ubuntu 22.04 This terminal tool can be an ideal complement to the use of GIT If you are a developer, you will like this application.
-
Tips for using the Linux test command
The [ command, often called a "test," is a command from the GNU Core Utils package, and initiates a conditional statement in Bash. Its function is exactly the same as the test command. When you want to execute a command only when something is either true or false, use the [ or the test command. However, there's a significant difference between [ or test and [[, and there's a technical difference between those commands and your shell's versions of them.
-
Filesystems and progressive deletion of things
There are two conjoined problems for filesystems when deleting things. First, in order to really delete things from a filesystem, you need to know what they are. So to delete a file, the filesystem needs to know specifically what disk blocks the file uses so the filesystem can go mark them as free in the data structures it uses to do this. This information about what disk blocks are used is not necessarily in memory; in fact, very little about the file may be in memory. This means that in order to delete the file, the filesystem may need to read a bunch of data about it off of the disks and then process it. For large files, there are several levels of this data in a tree structure of indirect blocks. This isn't necessarily a fast process, especially if the system uses HDDs and is under IO pressure already.
-
Batch transcode a folder of videos with Handbrake's CLI
But Handbrake's achilles heel, as a GUI-first application, is in a lack of easy batch operation. You can queue videos up one at a time, which is nice, but more recently, as I've ripped more TV seasons onto my NAS, I've wanted to transcode 5, 10, or 20 files at a time.
-
Day 22: the ::backdrop pseudo-element
It’s time to get me up to speed with modern CSS. There’s so much new in CSS that I know too little about. To change that I’ve started #100DaysOfMoreOrLessModernCSS. Why more or less modern CSS? Because some topics will be about cutting-edge features, while other stuff has been around for quite a while already, but I just have little to no experience with it.
-
How to date a recording using background electrical noise
When the mains hum produced by AC oscillations is picked up on a recording, its frequency fluctuations are picked up too. If we isolate and analyse the hum in a clip, we can measure these tiny variations in ENF. Because the variations are random, patterns don’t (or at least rarely) repeat. This means that the way in which the ENF varies during a recording can be used as a fingerprint that uniquely (ish) identifies the time at which the recording was made. We can timestamp a clip by comparing its ENF series to a database of past ENF values, and find the time at which the recording’s ENF most closely matches history. Second-by-second databases of past ENFs are widely available for many grids, sometimes published by grid operators themselves (for example, Britain’s National Grid), and sometimes by other organisations or individuals (for example, power-grid-frequency.org).
-
Understanding Unix filesystem timestamps
A lot of information on the Internet about filesystem timestamps are either outdated or simply misunderstood. Some people also tend to generalize a specific option's pros and cons across all setups, not knowing when the option is actually appropriate. For example, I might think that setting atime to on is unconditionally bad because it will have a detrimental effect on the performance of the filesystem without knowing that atime is required by some applications in order to function properly.