Script

find /[FOLDER_NAME]/* -mtime +[OLDER_THAN_DAYS] -exec rm -rf {} \;

Example deletes all files and folders in tmp folder that are older than 180 days: find /tmp/* -mtime +180 -exec rm -rf {} \;

Handling DNS records from bash, including import of bind config zone file: https://github.com/tmiland/Cloudflare-BIND-Zone-File-Upload/blob/master…

<?php 

define('DISALLOW_FILE_EDIT', true);

echo "\n DISALLOW_FILE_EDIT is: " . constant('DISALLOW_FILE_EDIT') . "\n";

//$constants = get_defined_constants();
//var_dump($constants); // pretty large list
?>

Key words: define defined constant constants

You can see a lot of good information for debugging and fixing errors on your Ubuntu server with journalctl and dmesg

journalctl --since "1 days ago"

journalctl --since "10 hours ago"

journalctl --since "12 hours ago" -p 3 -x --utc --no-pager

dmesg | less

dmesg -H --time-format iso| less

Resources:

https://unix.stackexchange.com/questions/50098/linux-network-troublesho…

Wordpress runs it's cron job automatically approximately every 10 minutes. Sometimes it is blocked by .htaccess or other server configuration. To avoid issues, it might be a good idea to run from the server crontab itself.

References:

https://kinsta.com/knowledgebase/disable-wp-cron/

https://wpbeaches.com/set-up-wordpress-wp-cron-php-to-run-manually/

find [FOLDER_NAME]/* -prune -mtime +14 -exec rm {} \;

Example bash on argument 1. It checks if HTTPS is up and if the domain-name is on the site. Most sites have the domain name on the front page somewhere: /usr/local/nagios/libexec/check_http -H $1 --ssl --onredirect=follow --string "$1"

If log file you can run grep on the following keywords: grep -i -e "critical" -e "invalid" -e "warning"  [LOGFILE.log]

Keywords: check_http

sudo resolvectl flush-caches

Before Ubuntu 22.04

Check DNS cache status: sudo systemd-resolve --statistics

Flush DNS cache: sudo systemd-resolve --flush-caches

A nice little guide: https://tecadmin.net/run-shell-script-as-systemd-service/

If you experience false characters in your mysqldump, you might want to try to set the encoding specifically. Example with latin1:

mysqldump -u [USER] -p --opt --skip-set-charset --default-character-set=latin1 [DATABASE_NAME] > [OUTPUT_FILE_NAME].sql

Check different encoding settings in mysql when using a specific database: show variables like 'char%';

More info and tips: https://www.toptal.com/php/a-utf-8-primer-for-php-and-mysql