Awk & sed Snippets for SysAdmins

Copying Data in a Restricted Environment

Consider this not-so-hypothetical scenario: you have some data on server_a that you would like to copy to server_b. Unfortunately, these two servers cannot communicate with each other. Nor do they have access to any common …

Raising Dead Services

I suppose you may say all of this can be just as easily done via systemd service config files. Well, yes and no. Yes, it can. And, no, not as easily. Not even close. Because …

IMDb Movie Title Parser in Bash

This is an update to the IMDb parser I wrote years back. From time to time IMDb makes small changes to their setup that break my script. This time they decided to start blocking curl, …

Plugging iPhone’s Privacy

Many recent publications , , suggest the iPhone is full of security holes threatening your privacy. The threat seems to be coming not so much from the phone’s operating system, but from the apps, …

Squeezing Video Files

All that crap I’ve been saving from YouTube, Facebook and whatnot tends to add up. As quality is not a huge concern here (not that it was very high to begin with), optimizing those video …

Finding Passwords in Logs and Shell History

Sooner or later it will happen: you type something after which you expect a password prompt then, without looking, you type the password. However, you fat-fingered the first command, and your password ended up in …

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 …

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 …

DevOps Obfuscation

Some years ago I’ve been reading “DevOps in Straight English” by Magnus Hedemark  and encountered the Release Frequency vs. Risk chart that supposedly illustrated the advantages of DevOps. It seemed convincing enough to not give …

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.

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; …

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.

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.

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.

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 the task of creating Web page screenshots.

The Future of Spaghetti Code

In his new book “The Future of Work: Robotics, AI, and Automation”1, Darrell West of the Brookings Institution makes some very extravagant predictions. Here’s a short but entirely sufficient summary from the book’s presentation by …

AWS CLI Cheat Sheet

The installation and configuration process for AWS CLI is fairly simple. The package itself is installed with pip (yum -y install python-pip):

Copying X11 Magic Cookies

I rarely use GUIs, but when I do, it’s from CLI and every time I run into the annoying MIT-MAGIC-COOKIE-1 data did not match error. It’s easy to fix, but it happens to me so …

Verify Network Port Access

There are several tools you can use to verify access to a remote network port: nc, tcping, telnet. Unfortunately, nc from the netcat package has been replaced by the one from nmap, which lacks the -z option, making …

Late Night Rant: Agile

CollabNet VersionOne has released it’s 12th annual “State of Agile” report. The survey involved more than 1,400 software professionals in various roles and industries over the fourth quarter of 2017.

Only 12% responded that their organizations …

Document Conversion with Unoconv

The other day I ran into the “Flexible Import/Export” article by Bruce Byfield in the March 2018 issue of Linux Pro Magazine and thought it could use some more detail. So here’s some more detail.