How to change MySQL root password in Debian / Ubuntu

Connect to MySQL Server using Linux terminal:

sudo mysql --user=root mysql

Run the following commands:

UPDATE mysql.user SET authentication_string=null WHERE User='root';
flush privileges;

Replace NEW_PASSWORD with your own.

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'NEW_PASSWORD';
flush privileges;
exit;

How to Flush the DNS Cache on Debian 10

To flush DNS cache in Debian GNU/Linux use command:

sudo systemd-resolve --flush-caches

If you get error message: “Failed to flush caches: Unit dbus-org.freedesktop.resolve1.service not found.“, enable the service on your system:

sudo systemctl enable systemd-resolved.service

Then again run the “systemd-resolve –flush-caches” command.

You can then check the statistics in order to make sure that your cache size is now zero, thus cleared. Run the following command in order to view the statistics:

sudo systemd-resolve --statistics

Configure certificate in HestiaCP

1. Backup current certificates in directory /usr/local/hestia/ssl/:

mv /usr/local/hestia/ssl/certificate.crt /usr/local/hestia/ssl/certificate.crt.old 

mv /usr/local/hestia/ssl/certificate.key /usr/local/hestia/ssl/certificate.key.old 

2. In directory /usr/local/vesta/ssl/ make symbol links to certificates, that we use on our site (for example: site.com):

ln -s /home/admin/conf/web/site.com/ssl/site.com.crt /usr/local/hestia/ssl/certificate.crt 

ln -s /home/admin/conf/web/site.com/ssl/site.com.key /usr/local/hestia/ssl/certificate.key 

3. Restart Hestia service:

service hestia restart

How to exit vim? And other required commands.

Vim is the most popular Linux text editor, it was created in 1978 and is used to present days.

Vim has two modes: “Command mode” where you can insert many commands, and “Insert mode” – where you can insert and edit text document. By default Vim open all documents in “Command mode”, to enter into the “Insert mode” – press button “i“.

The most asked question is – “How to exit Vim?” – it is very simple – in Command mode enter :q! and press Enter. This command exit Vim without saving any changes.

:q!

To save file – enter command :w <filename> and press Enter:

:w file.txt

To save file and exit Vim use command :wq and press Enter

:wq

How to uninstall program installed in Wine?

You just need to write in terminal command:

wine uninstaller

This command will start an Add/Remove applet similar to what you get in Windows, which will list your installed WINE programs.

Select program and press button “Uninstall”.

It was very simple 😉

How to set default browser in Debian Linux

To set default browser in Debian or Ubuntu open terminal and write command:

sudo update-alternatives --config x-www-browser

As you can see, we have four alternatives of browsers, installed in operating system, just enter number of browser and press Enter.

How to set permissions to files and folders in Linux terminal

There are there types of file permissions in Linux:

1. Owner permissions
2. Group permissions
3. Other permissions

Also you can set permissions for read, write and execute file for this three groups.

To set correct permissions for all files and folders in currend folder use command:

find . -type f -print0 | xargs -0 chmod 644
find . -type d -print0 | xargs -0 chmod 750

This commands will grant readm write, execute access for owner, read access for group and block all access for other users.

If you wand to grant access to files and folders for other users use commands:

find . -type f -print0 | xargs -0 chmod 665
find . -type d -print0 | xargs -0 chmod 751

Encrypt and decrypt files using GPG

To install GPG on your Debian/Ubuntu/Mint Linux operating system use command:

sudo apt-get install gpg

Default GPG folder is: /home/user/.gnupg. Generate private and public keys:

gpg --full-gen-key

Answer the several questions (encryption type: RSA, keysize: 4096 for better encryption, key expiration time, your name and email address) and press “O” if all changes are correct.

To view public keys use command:

gpg -k

To view secret gpg keys use command:

gpg -K

How to run custom file with Wine .exe in Linux Mint

To run Windows programs in Linux we use Wine. But how to open any file with exe program using Wine? For example we have 1.txt file. To run this file with notepad.exe use command:

wine "/home/user/notepad.exe" 1.txt

To associate some type of files with EXE program we can use shell script:

#!/bin/sh

QUICKPARLOCATION="/home/user/Notepad.exe"
PARAM=`winepath -w "$*" 2>/dev/null`
wine "$QUICKPARLOCATION" "$PARAM" &
exit 0

Put this file in /home/user/bin directory. Open file properties and in field “Open with” select Notepad.sh script:

How to install latest wine on Ubuntu or Linux Mint

The official WineHQ repository has a set of standard Wine packages that you can download and install on your system. Please follow these steps to do so:

Run the following command in the Terminal for adding i386 architecture before installing a 64-bit version of Wine:

sudo dpkg --add-architecture i386
Next add the WineHQ signing key:

wget -qO- https://dl.winehq.org/wine-builds/Release.key | sudo apt-key add -

Then run this command to import the other key for the WineHQ Repository:

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv F987672F

Now run the following command in order to add the relevant repository from the WineHQ:

sudo apt-add-repository 'deb https://dl.winehq.org/wine-builds/ubuntu/ bionic main'

Next update the Ubuntu package lists with the command:

sudo apt-get update

Now we can install latest stable version of Wine in Ubuntu or Linux Mint operating system:

sudo apt-get install --install-recommends winehq-stable