Install Certbot and it’s Nginx plugin with apt:

sudo apt install certbot python3-certbot-nginx

Verifies the syntax of your configuration edits:

sudo nginx -t

Reload Nginx to load the new configuration:

sudo systemctl reload nginx

To see the current setting of firewall:

sudo ufw status

Allows the Nginx Full profile and delete the redundant Nginx HTTP profile allowance:

sudo ufw allow 'Nginx Full'
sudo ufw delete allow 'Nginx HTTP'

Obtaining an SSL Certificate

sudo certbot --nginx -d example.com

Verifying Certbot Auto-Renewal:

sudo systemctl status certbot.timer

To test the renewal process, you can do a dry run with

certbot

:

sudo certbot renew --dry-run

fopen(/var/www/test.sdtokens.com/storage/app/public/images/mesk.webp): failed to open stream: Permission denied

Solution to the problem is running these commands to get the permissions

sudo chgrp -R www-data storage bootstrap/cache
sudo chmod -R ug+rwx storage bootstrap/cache

php artisan storage:link

The default

thousands_separator

is

,

which is 4th parameter. Without passing something else for the

thousands_separator

parameter, the

latency

was equal to

1,511.68525

The following PHP code caused problem in MySQL

$this->latency = number_format(microtime(1)-$_SESSION['startTime'], 5);

MySQL error:

SQLSTATE[01000]: Warning: 1265 Data truncated for column 'latency' at row 1

Solution to the problem is to specify the 4th parameter as an empty string

""

to get

latency

equal to

1511.68525

$this->latency = number_format(microtime(1)-$_SESSION['startTime'], 5, '.', '');

To list all cronjobs we simply run

crontab -l

command Cronjobs will be displayed without edit mode

First we open crontab to make changes to jobs by entering

crontab -e

command Then we activate edit mode by clicking

i

letter After editing we need to exit from edit mode by clicking

Esc

button Then we click

:wq

to save the changes

00 21 * * * php /var/www/html/services_cron/job_payments/index.php >> /var/log/job_payments.log 2>&1

By adding the line above, we tell

cronjob

to run the following file every day at

21:00

/var/www/html/services_cron/job_payments/index.php

And write output to the log file

/var/log/job_payments.log

To receive root permissions, we run the following command

sudo -i

Note: after running the above command, we need to enter the user's password

Postman request

Authorization type: Basic Auth
Username: usr
Password: pwd

PHP cURL request

curl_setopt($ch, CURLOPT_USERPWD, "usr:pwd");

Function

LAST_DAY

takes date and returns the last date of the month. In the example the result is

28

because the year is not leap year

SELECT 
    LAST_DAY('2021-02-15')

Creates trigger that runs

after

insert

and logs into

log

table

DROP TRIGGER IF EXISTS after_student_insert;

DELIMITER $$

    CREATE TRIGGER after_student_insert BEFORE INSERT 
    ON students
    FOR EACH ROW 
    BEGIN

    INSERT INTO log (description)
    VALUES ('One student inserted');

    END$$

DELIMITER ;

Converts radians back to degrees. Half of

PI

radians

1.5707963267948966

converted to degrees gives us

90

degrees.

PI

:

3.141592653589793

radians converted to degrees gives us

180

degrees.

SELECT
    DEGREES(1.5707963267948966),
    DEGREES(3.141592653589793)