Bash is one of the most powerful tools for doing all sorts of things in linux.
You can automate pretty much anything in bash and bellow are some useful commands.
Here are snippets of common bash commands I use.

Getting root permissions on a file inside of vi

:w !sudo tee %

Choose [L] to reload file as confirmation Or simply use visudo

logging into mysql as root

mysql -u root -p

changing password

mysqladmin -u root -p password newpass

secure installation

mysql_secure_installation

change a normal user password

mysqladmin -u user-name -p password newpass

Creating a new user

start mysql as root
mysql> CREATE USER yourname@localhost;
GRANT ALL PRIVILEGES ON mydb.* To yourname@localhost IDENTIFIED BY 'yourpassword'

Reset rails database

bin/rake db:reset db:migrate

destroy database and create it then migrate current schema

bin/rake db:drop db:create db:migrate

Duplicate current line in vscode

CTRL + SHIFT + NUMPAD2