I can write tons of bla bla about block devices, UUID and all related but the internet (especially wikipedia) is full of this so I will let you do a search if you are more interested about any of this.
So, I will keep it simple: you arrived here because you need a fast way to see the UUIDs of your block devices (call them hdds, partitions, as you like).
There are various tools and commands to achieve that. Read on.

Some of us (like me) still have old macbooks that came with superdrive. Naturally, we have replaced it long time ago with a secondary disk.
Wondering what to do with the now apparent "useless" eject button?
Find below some useful key combinations.

control+eject

Shows a dialog box with following options:
go to sleep
restart
shut down.

command+option+eject

Goes straight to sleep.

control+command+eject

It restarts.

control+option+command+eject

Performs shutdown.

Some of you already know that Windows zip combines several different functionalities:
- compression (like gzip),
- archiving multiple files into one (like tar),
- encryption (like gpg),
- plus some other.

Unix and Unix-like operating systems tend to split them so do not be surprised to have gzip for compression, tar for archiving files into one and gpg to encrypt.

So what we got here. A lot of spam and error message in mail.log:

Below you have few ways to create small consul clusters that will do nothing, just to show you how they can be made to connect to each other.

Useful things to work with

Here you have just small docker tricks to be able to see what consul is doing and what is exposing.

View container's logs by having them shown as they come, starting with the last 10 lines:

docker logs -f --tail 10 CONTAINER_NAME

In this tutorial, I will show you how to create a custom docker image and run a container on top of it.

I recently upgraded the debian version from 8 to 9 and my surprise was to not being able to connect to the newly upgraded server with my usual ssh key.
It turns out that beyond OpenSSH version 6.6, the "unsafe algorithms" have been removed, including my kinda old dss key.

All you have to do is to create a new one. I choose ecdsa: $ ssh-keygen -t ecdsa
Do not forget to put the newly pub key (e.g. the content of ~/.ssh/id_ecdsa.pub) in ~/.ssh/authorized_keys of the upgraded server.

Well, that was kinda short. Enjoy! :)

How to remove the contents from a File:

Note: this does not removes the file. It only clears the content, which is very useful if you want to clear a log on which an application writes continuously. This will ensure the filesystem's space is cleared (especially when cleaning huge logs) and the log is still accessible by the application.
PS C:\> Clear-Content file

The error I got today was related to speedtest-cli:

florians-MacBook-Pro$ speedtest
Traceback (most recent call last):
  File "/opt/local/bin/speedtest", line 6, in <module>
    from pkg_resources import load_entry_point
ModuleNotFoundError: No module named 'pkg_resources'

The macports package speedtest-cli is a terminal port for the popular speedtest.net. The source is available here.