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How to enable the MySQL/MariaDB general query logs

1. Enter to MySQL/MariaDB server command-line tool (change root with your username and password):

mysql -u root -proot

2. Set the general log file path:

SET GLOBAL general_log_file='/var/log/mysql/mycustom.log';

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  // For all the confusing Prometheus configuration and
  // regular expressions,
  // explained in examples.


  // Remember, there are default values for each item if it's missing.
  // regex is (.*),
  // replacement is $1,
  // separator is ;
  // ,and action is replace 

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Quick cheat sheet of helpful tmux commands

1. tmux new - Create and attach to a new session.
2. tmux new -s NAME_HERE - Create and attach to a new session named NAME_HERE.
3. CTRL-b, d - Detach (i.e. exit) from the currently-opened tmux session (alternatively, tmux detach). Note, this means press and hold CTRL, press b, release both, press d.
4. tmux ls - Show list of tmux sessions.
5. tmux a - Attach to the previously-opened tmux session.
6. tmux a -t NAME_HERE - Attach to the tmux session named NAME_HERE.
7. CTRL-d - Delete (i.e. kill) currently-opened tmux session (alternatively tmux kill-session).
8. CTRL-b, [ - Enter copy mode, and enable scrolling in currently-opened tmux session. Press q to exit.
9. CTRL-b, " - Split window horizontally (i.e. split and add a pane below).

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#!/usr/bin/perl

use Digest::HMAC_MD5 qw/ hmac_md5_hex /;
use DBI;
use URI::Escape;
use CGI;

print "Content-type: text/html\n";

my $q = CGI->new;

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• Flow of lua nginx module directives: https://openresty-reference.readthedocs.io/en/latest/Directives/
• body_filter_by_lua documentation: https://github.com/openresty/lua-nginx-module#body_filter_by_lua
• Following sample is from this site: https://groups.google.com/d/msg/openresty-en/5PWmL2f70x8/R2DUMsNUAgAJ

http { 
    proxy_cache_path /tmp/cache levels=1:2 keys_zone=cache:60m max_size=1G; 
    server { 
      listen 8080; 

      location /replace-body { 

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Email server based on Dovecot, Postfix, MySQL, Rspamd and Debian 9 Stretch

MySQL database setup

Install MariaDB as a database management system DBMS

sudo apt install mariadb-server

Create a new database named srvmail for a mail server:

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Whitelist IP addresses based on pre-filter policy

/etc/rspamd/local.d/multimap.conf:

  IP_WHITELIST {
      type = "ip";
      prefilter = true;
      map = "/${LOCAL_CONFDIR}/local.d/ip_whitelist.map";
 action = "accept";

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Kill user tty/pts sessions in Linux

Commands

• w: show who is logged on and what they are doing
• who: show who is logged on
• tty: show current users pseudo terminal
• ps -ft pts/1: get process id for the pseudo terminal
• pkill: signal process based on name and other attributes

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Ubuntu: Install Kernel and Set GRUB Default Kernel

Install Kernel

Install the default kernel:

sudo apt install linux-generic

Set GRUB Default Kernel

1. Find entrance from /boot/grub/grub.cfg
   • Get the $menuentry_id_option:

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# Create an access token for user "admin" with name "test-1234"
# POST /users/{username}/tokens/{name}
$ curl -i -u admin:admin -H 'Accept: application/json' -X POST 'http://127.0.0.1:12900/users/admin/tokens/test-1234?pretty=true'
HTTP/1.1 200 OK
X-Graylog-Node-ID: cd03ee44-b2a7-4824-be16-bb7456149dbd
Content-Type: application/json
Date: Mon, 08 Aug 2016 12:12:09 GMT
Content-Length: 139

{