Timeline
Adding and Removing sshd instances on CentOS 6
This is a process and a couple of script to allow you to setup an additional sshd service on an alternate port.
Creating a Chroot Jail for SSH Access
Just a quick collection of notes on - rather than a definitive guide to - setting up an SSH chroot jail on RHEL 6. The same should work on RHEL 7 and unrelated flavors. For the most part.
Late Night Rant: Facebook
According to media reports, since 2012, millions of Facebook and Instagram logins and plaintext passwords have been sitting on some internal Facebook system, accessible by thousands of the company's employees.
Notes on ownCloud configuration
The ownCloud file sharing application has been around for some time now, but somehow evaded my attention. My limited imagination makes me say "think of it us Dropbox hosted on the server in your basement".
GPG Encryption QSG
It always seems that just enough time has passed since the last time I worked with GnuPG for me to forget not just the exact syntax of these commands completely but the workflow in general. Here are some basics about using GnuPG and managing keys. If you need to know…Read More
Encrypting Log Data During Log Rotation
Most log files do not contain personally-identifiable information or other sensitive data. And even if they do, encryption of all personal data is not mandatory under GDPR. Still, on occasion, for testing and troubleshooting purposes you may want to log potentially sensitive information. It would be a very good idea…Read More
DevOps Obfuscation
Some years ago I've been reading "DevOps in Straight English" by Magnus Hedemark [efn_note]“DevOps in Straight English - Part 1 of 2 - Enter the Buzzword.” RHD Blog, 20 Apr. 2018, developers.redhat.com/blog/2014/01/15/devops-in-straight-english-part-1-of-2/. [/efn_note] and encountered the Release Frequency vs. Risk chart that supposedly illustrated the advantages of DevOps. It seemed convincing…Read More
The Unix Oriental
Placed quite appropriately in the "Security" category - my favorite Oriental cocktail recipe. Distinguishing it from the classic preparation, are absence of sweet vermouth and lime juice, as well as addition of just a couple of humble but crucial ingredients.
Gnuplot with Bash
OK, so both of these things have been around forever and will be around long after we're gone. It's worth your time to learn how to use the to together.
Multi-Dimensional Arrays in Bash
Bash does not support multi-dimensional arrays, but there is a way to imitate this functionality, if you absolutely have to.
Asciinema Notes
Asciinema is an awesome tool for recording your console sessions. It's great for documenting processes and, in general, showing people how shit works: one look is worth a thousand words, as they say. Unfortunately, I don't use asciinema often enough to remember the syntax and so here we are.
File Compression Testing
For some reason I haven't used zip much on Linux, sticking to the standard tar/gzip combo. But zip seems to be a viable alternative. While not as space-efficient, it is definitely faster; syntax is simple; and, if you need to share the archive with a Windows user, he doesn't have…Read More
Measure DNS Server Performance
This is not an entirely proper way to benchmark a DNS server, but, in a pinch, it should give you some idea of its responsiveness and stability.
The Facebook Fracas
The Facebook privacy saga is getting ridiculous. You’re using a free service that you signed up for - nobody was holding a gun to your giant head. And it’s not Gulag either: just delete your profile, uninstall the damned app, and forget Facebook ever existed.
Killing Process Network Access
Imagine this scenario: a particular process on your server is connecting to a host outside your internal network and you don't like that. On the other hand, you can't just kill that process because you need it.
Generating and Running Multiple Scripts
Admittedly, this has a limited range of practical applications and is more of a scripting exercise. The command shown here generates a bunch of temporary scripts each containing the sleep command for up to one minute.
Removing Chef Server Installation
Just a quick note on how to completely remove (more or less) Chef server installation from a CentOS/RHEL box.
Installing t CLI power tool for Twitter
The 't' is an excellent Ruby-based CLI utility for interacting with the Twitter API written by Erik Berlin. This is certainly not the only such tool available, but, in my estimation, it is the most full-featured and expertly-written. No amateur-hour coding here.
Keeping Abreast with Filesystem Changes
The inotify is a Linux kernel sybsystem for notifying user-space applications of filesystem changes. I always thought this exceptionally handy utility was under-appreciated or at least underutilized.
Resizing Photos for Instagram
Instagram is being a pain in the neck by limiting support to specific aspect ratios. Currently, you can only upload photos of no less than a 4/5 ratio for portrait mode and the peculiar 16/8.377 ratio for landscape shots, which is just a smidgen over the standard 16/9. Neither ratio…Read More
Curated Downloads
A curated list of useful or otherwise interesting (to me) downloads. These are all things I installed, configured and, at the very least, played with for a few days. I will add a lot more stuff to this list, time permitting. Please do offer suggestions as comments. If you fancy…Read More
Grouping Output of SSH via xargs
To make a long story short, I have a list of servers where I need to execute a command and get back the output. Using a for loop to run SSH with key authentication is the usual approach, except in this case accessing one server at a time was taking…Read More
Exporting WordPress to Markdown
WordPress is my favorite CMS, but the complexity and security issues introduced by PHP and the database are unnecessary in some cases. Migrating to a static Web site may be a better option when it is all you need.
QNAP NAS Performance Analysis
The QNAP Resource Monitor utility available via the Web UI provides a lot of useful functionality with good visual presentation. However, sometimes you need just a little bit more detail to help track down a particularly elusive performance issue.
Auto-Update /etc/hosts
This was a silly solution to a silly problem, but may come in handy in the future for other things. A user process was establishing frequent connections to a handful of FQDNs. Not having any IP caching capability, every connection attempt was preceded by DNS lookup.
