Linux: Command-line utilities for obtaining information

There are many ways to ask a Linux machine how it’s doing. I’ve collected a few of them, mostly for my own reference. I guess I’ll add more items as I run across new ones. General Info inxi -Fxxxz (neat output, but makes the system send me security “password required” alert mails because of attempts [...]

Linux: Atheros QCA6174′s Bluetooth disappearing after reboot

When Bluetooth goes poof Having rebooted my computer after a few months of continuous operation, I suddenly failed to use my Bluetooth headphones. It took some time to figure out that the problem wasn’t with the Cinnamon 3.8.9 fancy stuff, nor the DBus interface, which produced error messages. There was simply no Bluetooth device in [...]

VIA VL805 USB 3.0 PCIe adapter: Forget about Linux

TL;DR Bought an Orico PCIe adapter for USB 3.0 for testing a USB device I’m developing (PVU3-5O2I). It has the VL805 chipset (1106/3483) which isn’t xHCI compliant. So it works only with the vendor’s own drivers for Windows, which you’ll have to struggle a bit to install. Attempt with Linux That the device is detected [...]

ImageMagick convert to scale jpgs

Instead of using my scanner, I put my cell phone on some kind of stand, and shot a lot of paper documents (voice activation is a blessing). But then the files are unnecessarily large. Don’t need all that resolution. So $ for i in * ; do convert “$i” -scale ’33%’ -quality 75 “smaller/scan_$i” ; [...]

Linux: Writing a Windows MBR instead of grub

On a test computer, I use /dev/sda1 to contain whatever operating system I need for the moment. At some point, I installed Linux Mint 19.1 properly on that partition, and then I wanted to return to Windows 10. After writing the Windows 10 image to /dev/sda1, I got a message from grub saying it didn’t [...]

systemd / DBus debugging starter pack

Introduction Trying to solve a 90 second wait-on-some-start-job on each boot situation, I found that there’s little info on how to tackle a problem like this out there. Most web pages usually go “I did this, hurray it worked!”, but where do you start solving a problem like this if none of the do-this-do-that advice [...]

Solved: systemd boot waits 90 seconds on net-devices-eth0

Introduction After installing wireshark (and tons of packages it depends on) on a rather fresh and bare-boned Debian 8 (Jessie), I got the “A start job is running for sys-subsystem-net-devices-eth0.device” message for a minute and half on every boot. It was exceptionally difficult to find the reason, because so many packages were installed along with [...]

When mplayer plays a black window (or: Cinnamon leaking GPU memory)

The incident All of the sudden, playing videos with Mplayer opened a black window. Sometimes going fullscreen helped, sometimes it didn’t, sometimes with video playing but without OSD. ffplay worked, but somewhat limping. Setting: Linux Mint 19 on an x86_64, with a couple of fanless GeForce GT 1030 graphics cards and Cinnamon 3.8.9. Mplayer’s output [...]

Perl, DBI and MySQL wrongly reads zeros from database

TL;DR: SELECT queries in Perl for numerical columns suddenly turned to zeros after a software upgrade. This is a really peculiar problem I had after my web hosting provider upgraded some database related software on the server: Numbers that were read with SELECT queries from the database were suddenly all zeros. Spoiler: It’s about running [...]

Replacing ntpd with systemd-timesyncd (Mint 18.1)

Introduction It all began when I noted that my media center Linux machine (Linux Mint 18.1, Serena) finished a TV recording a bit earlier than expected. Logging in and typing “date” I was quite surprised to find out that the time was off by half a minute. The first question that comes to mind is [...]