Featured »


Processing Videos with ffmpeg and Lightroom

October 12, 2020 – 1:52 pm

On occasion I wondered how to apply advanced photo filters to my lackluster GoPro and drone videos. You know, not the basic exposure/contrast/saturation or the cheesy special effects you find in video editors, but something …

Read the full story »

Unix and Linux network configuration. Multiple network interfaces. Bridged NICs. High-availability network configurations.


Reviews of latest Unix and Linux software. Helpful tips for application support admins. Automating application support.


Disk partitioning, filesystems, directories, and files. Volume management, logical volumes, HA filesystems. Backups and disaster recovery.


Distributed server monitoring. Server performance and capacity planning. Monitoring applications, network status and user activity.

Commands & Shells

Cool Unix shell commands and options. Command-line tools and application. Things every Unix sysadmin needs to know.

Applications, Featured »

Processing Videos with ffmpeg and Lightroom

October 12, 2020 – 1:52 pm

On occasion I wondered how to apply advanced photo filters to my lackluster GoPro and drone videos. You know, not the basic exposure/contrast/saturation or the cheesy special effects you find in video editors, but something you can do to a photo in, say, Photoshop or Lightroom.

Read the full story »

Searching Twitter

October 11, 2020 – 1:50 pm

Here are just a few hopefully useful tips for searching Twitter to get more relevant results and buy cheap twitter followers.

Bash Scripts and MySQL

October 10, 2020 – 1:49 pm

I frequently use MySQL to store data collected or processed by various shell scripts. The database comes in handy when massaging data with good old awk and sed gets too cumbersome.

Bulk Create Linux Users using Salt

October 9, 2020 – 1:48 pm

Recently I ran into a situation where hundreds of VMs recently built via OpenShift/Ansible automation were missing an important local user account used for security audits. While our automation guys were working on tracking down …

Checking Linux Account Password

October 8, 2020 – 1:46 pm

On occasion you may need to check if an account has a specific password. For example, when you build VMs, you may use some default passwords for some default accounts (i.e. root) that should be …

Coronavirus Stats in Bash

October 7, 2020 – 1:40 pm

The result of my morbid fascination with the coronavirus situation is this quick bash script that parses Johns Hopkins University coronavirus data to generate a quick report for the current date for the specified countries.

Updating Lynis

October 6, 2020 – 8:22 am

Lynis is an excellent security audit tool for Linux and various Unix derivatives. I have a small wrapper script that runs Lynis via a cron job, does a selective diff with the previous run’s output, …

Hiding Passwords

October 5, 2020 – 8:20 am

I’ve touched on this subject previously, but suddenly felt I should repeat myself. The big issue with using passwords from command line is shell history.

Convert Code Snippets to PNG

October 4, 2020 – 8:19 am

On occasion I find myself struggling posting code on discussion forums that don’t handle code formatting all that well. What would’ve helped is some quick and easy way to convert code to an image file …

Backup Options for Raspberry Pi

October 3, 2020 – 8:16 am

Just about every Raspberry Pi I used suffered the same fate: the micro SD card died. It is generally accepted that the expected lifespan of an SD card is around ten years of normal use.

Affordable Linux Server

October 2, 2020 – 8:14 am

A friend asked me what server I would recommend to run Linux. Yes, a very broad query. After a few followup questions we’ve determined the server will be used to run VMs, or Apache, or …

Backing Up WSL Images

October 1, 2020 – 8:13 am

Microsoft’s WSL is interesting. I’d go as far as to say that I like it. The mistake here would be to forget that your Linux image is running under Windows, with everything this entails. Making …

Home-Brew Ransomware Defense

October 1, 2020 – 8:10 am

The first well-known case of ransomware was documented in 1989. The so-called AIDS Trojan was delivered on a floppy disc; encrypted data; demanded $189.00 (nearly four hundred bucks in today’s money) as a “license fee”. …

Validating HTTPS Cache Peers for Squid

January 6, 2020 – 12:38 am

I have a squid proxy server that uses a long list of authenticated cache peers in a round-robin configuration. The process looks something like this:

Updating PHP 5.6w to 7.1u on CentOS 6.10

December 30, 2019 – 9:53 pm

This is mostly just a note to self. As I mentioned previously (probably more than once), I very much dislike systemd and will stick with CentOS 6 for as long as possible. Having said that, …

Analyzing atop Logs with atopsar

December 26, 2019 – 9:52 pm

I have discussed atop previously but concentrated primarily on how to run it and how to collect data. Now I’d like to spend some time talking about ways to analyze the data collected with atop.

Appending Filenames

December 22, 2019 – 9:51 pm

If you google how to append, say, current timestamp to the filename in Bash, almost every suggestion boils down to something really basic along the lines of mv $somefile $somefile_$(date +’Y%-%m-%d’). Technically, this is correct …

Verifying SNMP Connectivity on Multiple Hosts

December 19, 2019 – 9:50 pm

I needed to check if SNMP was accessible on whatever live servers that existed in a particular subnet. Here’s a quick script to do this.

Selecting Time Ranges from Logs, Part 2

December 16, 2019 – 9:47 pm

A couple of years ago I wrote an article about selecting specific time ranges from log files. I proposed two options: either convert all timestamps to epoch format (a CPU-intensive process) or rely on regex …

Bulk-Adding IPTables Rules

December 12, 2019 – 9:46 pm

I’ve been using my mod of this handy script to block countries with iptables. One issue with the script is that it is adding rules one-by-one using the iptables -A syntax. This is the proper …

Automatically Block Frequent Visitors

December 9, 2019 – 9:45 pm

I had a few similar scripts floating around this site, but this one is a bit more all-inclusive and better organized. The script will analyze your firewall/whatever access log and block particularly active visitors.

Windows 10 Upgrades

December 6, 2019 – 9:44 pm

I did the only sensible thing and disabled automatic updates on my two Windows 10 laptops. Microsoft’s belated foray into the world of CI/CD for releasing Windows patches suffers from limited automated testing.

Detecting Blurry Photos with ImageMagick

December 3, 2019 – 9:43 pm

Here’s a typical scenario: I go to a birthday party where everyone knows I’m a shutterbug, so I have to bring my camera. As time goes by and blood alcohol concentration rises and attention to …