Backing up or restoring from a CF card, usb stick or similar using dd

 The basic format of the commands are as follows;

dd if=/dev/sdb of=/tmp/backup-file

dd if=/dev/backup-file of=/dev/sdb

Debian keyboard layout

For issues with Debian keyboard layout, firstly see here

Removing gpg keys

gpg keys can normally be removed from the /etc/apt/trusted.gpg.d directory.

This would be in the format of sudo rm ...

However if the keys are stored in /etc/apt/trusted.gpg then we need to use;

sudo apt-key del [keyid] which is fine for older? systems where the following shows a list of the keys;

sudo apt-key list

and the keyid field would be shown but on modern systems that seems not to be the case, so this time, we again use sudo apt-key list but note the last 8 characters of the long number and this becomes the keyid which can then be removed by using;

sudo apt-key del [keyid]

gzip -l shows incorrect uncompressed file size

In some cases the incorrect uncompressed file size is reported when running the following command;

gzip -l myfile.gz

A work around is the use the alternative below;

zcat myfile.ga | wc -c

[source]

Resize a VistualBox disk

To resize a virtualbox disk, you can do it from the GUI on current systems;

MySQL current date

 The following are just examples of the use date offsets;

SET @timeframe=now()-interval 2 year; 

SELECT ...
WHERE o.doe >= @timeframe

SET @timeframe = DATE_SUB(CURDATE(), interval 1 day);
SELECT ...
WHERE o.doe >= @timeframe and o.doe <= @timeframe

The former will deal with the full date/time stamp, while the latter will consider only the date and is good for when we need to find results for a particular day for example.

xfce Desktop and icons dissapear

 Running xfdesktop in the terminal seems to resolve.

MySQL error when trying to create a function

This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable)

Power Over Ethernet - PoE

 A point on PoE

Tensorflow Machine Learning models

 PLACEHOLDER