Awk & sed Snippets for SysAdmins
Books have been written on the subject of awk and sed. Here's a small sample of commands I put together over the years that are useful for everyday system administration tasks. Most of these tasks involve reformatting strings and files, which is why I decided to bundle tr, cut, and…Read More
Finding Duplicate Photos
Being a shutterbug and a digital hoarder can get expensive. A couple of days ago, my TerraMaster D5-300 5-bay DAS crashed. Again. This time it was the power supply. I replaced it only to discover that my RAID 5 volume is toast. It was still rebuilding the failed drive I…Read More
Inventory Network Services with Nmap
With the growing number of network-enabled devices in your home, meaningful security becomes elusive. The first step to addressing the situation is knowing what you have. A few examples below use the nmap utility to scan your local network and detect active devices and services.
Benford’s Law in Bash
Benford's Law, a curious mathematical phenomenon, asserts that in many real-world numerical datasets, the leading significant digit is more likely to be small. This observation, far from being merely intriguing, can be a powerful tool for distinguishing authentic data from manipulated or fabricated ones.
Maryland Renaissance Festival
The second largest fairy of its kind in the US has been operating in Crownsville, MD, sine 1977. The event is centered around a permanent Tudor-style village and is open in September and October. Every year the theme of the festival is based on a different year of King Henry…Read More
Collatz Conjecture in Bash
The Collatz conjecture is a math problem from the mid-1930s. It involves an algorithm that starts with any positive integer, and then each following number is made by taking the previous number and changing it. If the number n is even, you make it half of what it was (n/2).…Read More
Simple Math from Bash Command Line
Chances are, most shell scripts you write will require some math operations, even if it's something as simple as incrementing a variable inside of a loop. As with everything else in Linux, there are multiple ways of accomplishing the same task. Here's a quick look at some of the options.
Focus Stacking with Lightroom and Photoshop
Not the usual topic for this blog and not the most comprehensive guide on the subject out there, but here I go anyway. Focus stacking combines multiple photos taken at different focal distances into an image of greater depth of field.
Peculiar Linux Command-Line Tools
Some Linux CLI commands I type every day, probably hundreds of times. Others - on a rare occasion. But there's a category of truly esoteric utilities tailor-made for some singular and often exotic purpose. I heard of many - if not most - of these utilities, but it's difficult to…Read More
NFS I/O Stats with Logging
The nfsiostat is an excellent tool for analyzing NFS performance. The only major problem with this utility is that it's designed to be used interactively. It does not have logging or timestamping capabilities. I needed to get information about NFS mount performance during a nightly backup, and I didn't really…Read More
Inventorying NFS Mounts and Mount Options
As time goes by, NFS mounts multiply like rabbits. Added by many different people over the years, these entries present a dizzying variety of mount options - most are a copy-paste job that makes little sense. All this variety inevitably results in performance issues that are difficult to pin down.
Joining Text Files and Data Columns
When working with application logs and other text files, it is often useful to view the contents of different source files side-by-side. Here we will take a quick look at various command-line methods for joining data columns from different files.
Identify Overused Words
The issue of overused words is a tricky one. For me, the problem occurs when I revisit my writing a few days later and make a few edits. I may find a word I would like to replace with a better match, forgetting that the same word was already used…Read More
Automating Web Page Screenshots
Automatic Web page screenshots are commonly used for various monitoring tasks, such as detecting copyright infringement, website defacement, and other legal and security matters. Automatic screenshotting can also be a useful tool for researchers, developers, and journalists. There are free and open-source tools out there that can help you automate…Read More
Working with SD Cards for Photographers
What do I recall from my extensive overland trips in the past few years? Not much, to be honest. It was just a blur of driving, looking for gas stations, trying to reserve camping spots or motel rooms, and - yes - joggling camera batteries and SD cards. But I…Read More
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