Just in case I ever need it again: Extracting all frames from an mjpeg video as jpegs is easy and very fast with ffmpeg, because it does not need to decode and encode the pictures, just prepend the DHT to each one: [bash] ffmpeg -i inputmpeg.avi -c:v copy -bsf:v mjpeg2jpeg frame_%d.jpg [/bash] Source ffmpeg documentation.

I just tried to install Webmin on a fresh install of Ubuntu 18.04 Server in the same way as I did on 16.04. Unfortunately it failed on the command [bash] apt install webmin [/bash] because the package apt-show-versions was not found. I solved this by adding the universe repository to apt with [bash] sudo add-apt-repository … Continue reading Installing Webmin on Ubuntu 18.04 Server →

Parted is a flexible tool for working with partition tables under Linux. Unfortunately it sometimes seems rather stupid. For example when you create a new partition you may get the warning "The resulting partition is not properly aligned for best performance". It could then of course proceed to suggest the proper alignment, but it doesn't, … Continue reading Creating a properly aligned partition with parted →

In theory it is easy to detect when the user plugs in a USB device to a Linux computer and notify him what was detected. In practice it's still easy as long as you know how to do it. First thing to do is add a file to[bash]/etc/udev/rules.d[/bash] The file name should follow the convention … Continue reading Write the name of a newly connected USB device to the console in Linux →

Sometimes you need a large file for testing purposes or just to take up space that should not be available on the file system. There are several options on how to generate such a file on Linux: The traditional method is using dd, setting if (in file) to either /dev/null or to /dev/random. A more … Continue reading Create a large file filled with zeros on Linux →

Keeping track of changes in the Linux configuration can be a chore but sometimes it is vital to know what was changed. As a software developer I am used to using version control systems for source code, so why not use one for configuration files? Enter etckeeper a tool that does exactly that: It tracks … Continue reading etckeeper – version your /etc directory →

Let's say you have a directory of backups looking like this: .\ \-> user1\ \-> [date1]_[time1] \-> [date2]_[time2] \-> some more sub directories with date and time in the name \-> user2\ \-> [date3]_[time3] \-> [date4]_[time4] \-> some more sub directories with date and time in the name \-> some more user sub directories Where … Continue reading Deleting old backups →

Since the last time I looked up how to configure the Web Proxy, apparently somebody came up with WPAD - the Web Proxy Auto-Discovery Protocol (Or maybe I simply missed it). The idea is quite neat: In the dhcp server, add an entry where the browser can request an url which in turn returns the … Continue reading Web Proxy Autoconfiguration →