Remote database server backup of all databases (all schemes) with mysqldump example with comments. And restore command with retained comments in procedures (for example).)

mysqldump_schema_backup_example.sh

#!/bin/bash

# For example: https://dev.mysql.com/doc/refman/8.0/en/mysqldump.html 
# --no-data Do not dump table contents
# --triggers Do add triggers too
# --host Dump data from the MySQL server on the given host. The default host is localhost.
# --port For TCP/IP connections, the port number to use.
# --all-databases Dump all tables in all databases. 
# -u The user name of the MySQL account to use for connecting to the server.
# --verbose Verbose mode. Print more information about what the program does.
# -p The password of the MySQL account used for connecting to the server. The password value is optional. If not given, mysqldump prompts for one. If given, there must be no space between --password= or -p and the password following it. If no password option is specified, the default is to send no password.
# > Redirect the output to file, for example
# install mysqldump (it's actually part of mysql client software) on ubuntu: sudo apt install mysql-client
# maybe add --skip-lock-tables

mysqldump --no-data --host some_server_host --port some_server_port --all-databases --routines --events -u mysql_user -p --verbose > db_schemes_backup_file.sql

# Restore with retained comments (default is --skip-comments (discard comments)):
sudo mysql -u USER -p -h HOST -D DATABASE --comments < db_backup_file.sql 

Example with removing the DEFINER from everything:
mysqldump -u mysql_user -p -h localhost --port 3306 --routines --events --comments DATABASE_NAME --verbose | sed -e 's/DEFINER[ ]*=[ ]*[^*]*\*/\*/' | sed -e 's/DEFINER[ ]*=[ ]*[^*]*PROCEDURE/PROCEDURE/' | sed -e 's/DEFINER[ ]*=[ ]*[^*]*FUNCTION/FUNCTION/' > local_db_backup_20200612.sql
https://stackoverflow.com/questions/9446783/remove-definer-clause-from-mysql-dumps#comment72272227_9447215