What: A list of not-now useful links
Why: Limited memory 😉
How: –

Tools

Vagrant

Virtual Box

Resizing virtual box disk space, the easy way
GParted live image

Install guest additions in Ubuntu

sudo apt-get install virtualbox-guest-dkms

Java

https://developers.redhat.com/blog/2017/03/14/java-inside-docker/

Ember

https://medium.com/@ruslanzavacky/ember-cli-fingerprinting-and-dynamic-assets-797a298d8dc6

Docker

https://developers.redhat.com/blog/2017/03/14/java-inside-docker/

Docker an iptables

Sound recording

http://www.upubuntu.com/2013/05/how-to-record-your-voice-from.html

Machine learning

deeplearnjs

Programming

Ternary numbers

Python 3 program to convert a decimal number to ternary (base 3)

Data

General

Pandas data profiling

Conversion

Convert audio to base64

Linux

Go back to older kernel after update

Add a second hard drive (also working for vms)

Ubuntu not starting to graphical mode, flickering

Hang at boot on old machines

See https://www.youtube.com/watch?v=ZZBTSUbzT0g.

Add acpi=force in /etc/default/grub in line GRUB_CMDLINE_LINUX_DEFAULT and apply settings:

sudo update-grub

Ubuntu

If you would like to use a usb serial connection (for example to connect an ESP32), make sure the linux-modules-extra is installed (which is not the case in default cloud versions of Ubuntu). You can install it via:

sudo apt install linux-modules-extra-$(uname -r)

Windows

Links to user folders

1. Copy folder to new location
2.

mklink /J "absolute path to old location" "absolute path to new location"

Show symbolic links

dir /AL /S "folder"

VCS

Git

Beautiful log

git config alias.lg "log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --date=relative"

Use it like:

git lg --all

Development

Joels Test

Hallway test

Python https server

Creating self-signed SSL certificates with OpenSSL

Serial console

https://www.cyberciti.biz/hardware/5-linux-unix-commands-for-connecting-to-the-serial-console/

Client – Server

Get server certificate

See: https://superuser.com/a/641396.

openssl s_client -showcerts -connect server.edu:443 /dev/null|openssl x509 -outform PEM >mycertfile.pem

Systemd

https://wiki.ubuntuusers.de/Howto/systemd_Service_Unit_Beispiel/

https://www.freedesktop.org/software/systemd/man/systemd.service.html

Activate caching for client side on apache2

Enable apache module:

1 2	a2enmod headers sudo systemctl apache2 restart

Create .htaccess file in the specific directory (adjust max-age to the number of seconds you want the resource to be cached):

<IfModule mod_headers.c>
<FilesMatch "\.(gif|ico|jpeg|jpe|png|css|js)$">
Header set Cache-Control "max-age=86400, public"
</FilesMatch>
</IfModule>

Set different port in apache2

See: https://stackoverflow.com/a/26064554.

Images

Identify image format

1	identify -format "%wx%h %C"

For format options see: ImageMagick.

Resize image

1	convert -resize x\>

IoT

Raspberry and Ubuntu

Install Ubuntu on Raspberry

https://ubuntu.com/download/raspberry-pi

Getting audio to work over hdmi

Add the following line to /boot/firmware/usercfg.txt and reboot:

1	dtparam=audio=on

Increase gpu memory