change timezone on Ubuntu 18.04 (for example)

 

Set via two procedures as below.

 

Use dpkg-reconfigure as an alternative

#  sudo dpkg-reconfigure tzdata

 

https://linuxize.com/post/how-to-set-or-change-timezone-on-ubuntu-18-04/ 

 

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change hostname on ubuntu 18.04 (for example)

 

Procedure:

show hostname

hostnamectl

set new host name

sudo hostnamectl set-hostname <newname>

edit hostname file

edit instance of name in local host entry for the host name

log out and back in, will show in bash prompt

https://linuxize.com/post/how-to-change-hostname-on-ubuntu-18-04/

 

 

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Error using convert from various input media to pdf

 

There is a command which is part of Imagemagick which included Gimp to consolidate and create images into other files, in particular PDF files.

Initially Imagemagick installed a policy file, but recent changes tightened access rules for a number of formats which are actually essentially programming languages.  This is true of postscript and PDF files.

The following will enable the writing of PDF files again for use by convert.  The reason to disable it is it is potentially a vector into compiling programs with file write privileges and was blocked as a precaution.

Find the line below and change "none" to "read/write"

Source of information:

https://cromwell-intl.com/open-source/pdf-not-authorized.html

 /etc/ImageMagick-6/policy.xml should contain:

<policy domain="coder" rights="none" pattern="PDF" />

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Google GPG error in update of repos for Ubuntu 16.04

 

Looks like ubuntu has fouled up the capability to do pgp analysis on keys from repositories because on the 16.06 they have obsoleted the code to do the verification.

https://www.omgubuntu.co.uk/2017/08/fix-google-gpg-key-linux-repository-error 

 

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disable screen blank on rasbian buster

 

 https://www.raspberrypi.org/forums/viewtopic.php?t=244001

 

Code: Select all

xset s off
xset -dpms

Code: Select all

sudo vi /etc/xdg/lxsession/LXDE-pi/autostart

 

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Install mysql / mariadb on raspbian example

 

 

 

How to install MySQL database on raspberry pi

1 sudo apt-get install mysql-server.

2 sudo mysql_secure_installation. 5)Please hit Enter for current root password.

3 sudo mysql -u root -p. ...

4 show databases; ...

5 CREATE DATABASE Demo; ...

6 USE Demo; ...

7 CREATE USER 'admin'@'localhost' IDENTIFIED BY 'admin'; ...

8 GRANT ALL PRIVILEGES ON Demo.* TO 'admin'@'localhost';

 

Example and more details

how-to-install-mysql-database-on-raspberry-pi 

 

 

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Ubuntu upgrade notes 20.04 20.10

 

 

note that at do-release-upgrade, there will be a long pause, then an "are you sure prompt" that has to be responded to to complete.  Then some goods will be downloaded and another response required.

 

Upgrade will proceed after that.

 

 

$ sudo apt update
$ sudo apt upgrade
$ sudo apt dist-upgrade 

$ sudo apt autoremove

 

 Configure the release upgrader. Open and edit the

/etc/update-manager/release-upgrades file and ensure that the Prompt variable is set to normal.

 

 [DEFAULT]
# Default prompting behavior, valid options:
#
#  never  - Never check for a new release.
#  normal - Check to see if a new release is available.  If more than one new
#           release is found, the release upgrader will attempt to upgrade to
#           the release that immediately succeeds the currently-running
#           release.
#  lts    - Check to see if a new LTS release is available.  The upgrader
#           will attempt to upgrade to the first LTS release available after
#           the currently-running one.  Note that this option should not be
#           used if the currently-running release is not itself an LTS
#           release, since in that case the upgrader won't be able to
#           determine if a newer release is available.
Prompt=normal

$ sudo do-release-upgrade

Reboot the Ubuntu system.

 

 

reference link 

-

 

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