Dynamic DNS

FQDN (Fully Qualified Domain Name)

• Pc name: "deb"
• Domain name: "bar.com"

O FQDN is: "deb.bar.com."


Alternatives

[1] http://neorouter.com/products-nrfree

TensorFlow Example for learn

Examples:

[1] https://github.com/aymericdamien/TensorFlow-Examples/tree/master/notebooks/3_NeuralNetworks



Tensor decomposition (for read)

[1] https://github.com/Large-Scale-Tensor-Decomposition/tensorD
[2] https://smile-lab-tensord.readthedocs.io/en/latest/guide_decomposition.html

private VPN Services

Resources:

[1] Compare https://www.wizcase.com/best-vpns-for-brazil
[2] Perú https://www.vpnfan.com/blog/best-lima-vpns/
[3] Providers Pt https://canaltech.com.br/internet/descubra-por-que-usar-uma-vpn-e-veja-como-escolher-a-melhor/

Postgres Lectures for improve performance

References:
[1] https://revs.runtime-revolution.com/streaming-data-in-postgres-43c502a6732
https://revs.runtime-revolution.com/streaming-data-in-postgres-43c502a6732
[2] https://blog.timescale.com/scalable-postgresql-high-availability-read-scalability-streaming-replication-fb95023e2af/
[3] https://www.pipelinedb.com/
[4] https://www.citusdata.com/blog/2017/11/08/faster-bulk-loading-in-postgresql-with-copy/
[5] https://dzone.com/articles/postgresql-vs-hadoop

Stream Music from your Linux PC to Android Cellphone Speaker

1) SoundWire

2) WiFiAudio Server for Linux 64bit

References:
[1] Client https://appuals.com/stream-audio-pc-android-device/
[2] Server http://georgielabs.net/
[3] http://wifiaudio.boards.net/thread/2/wifiaudio-support-links-download-application
[4] WifiAudio Sever Linux 64bits http://wifiaudio.boards.net/attachment/download/6

Linux Remote Desktop

sudo apt-get update
sudo apt-get install xrdp 

#desktop

sudo apt-get install mate-core mate-desktop-environment mate-notification-daemon

#setting session

sudo sed -i.bak '/fi/a #xrdp multiple users configuration \n mate-session \n' /etc/xrdp/startwm.sh

#firewall

sudo ufw allow 3389/tcp

#Use remmina desktop to connect

Extra

service --status-all

printf 'Desktop: %s\nSession: %s\n' "$XDG_CURRENT_DESKTOP" "$GDMSESSION"

References:
[1] Setting xrdp https://medium.com/@vivekteega/how-to-setup-an-xrdp-server-on-ubuntu-18-04-89f7e205bd4e
[2] https://websiteforstudents.com/connect-to-ubuntu-16-04-17-10-18-04-desktop-via-remote-desktop-connection-rdp-with-xrdp/
[3] Print desktop name and session
https://askubuntu.com/questions/72549/how-to-determine-which-window-manager-is-running

SSH Skip port forwarding

Instant terminal sharing
https://tmate.io/


Share your UNIX terminal in seconds!
https://www.teleconsole.com/

Share local machine port to public access
https://serveo.net/
https://github.com/milio48/serveo
$wget https://raw.githubusercontent.com/milio48/serveo/master/serveo.sh 

$./serveo.sh tcp 5432 0

vs ngrok
Serveo is an excellent alternative to ngrok. Serveo was inspired by ngrok and attempts to serve many of the same purposes. The primary advantage of Serveo over ngrok is the use of your existing SSH client, so there's no client application to install.

Other slight advantages include preservation of URLs across reconnect for free (ngrok allows this only for paid accounts) and in-terminal request inspection and replay (ngrok uses a web interface).

vs OpenSSH

Using Serveo instead of OpenSSH frees you from having to configure and maintain a server. It also handles HTTPS and subdomain generation, two features that complicate a typical SSH port-forwarding setup.

Apache Guacamole is a clientless remote desktop gateway


http://guacamole.apache.org/


Manual mode (A like to connect to B)

PCA ----+----  PCB
            |
          PCX

Server Side (PCX Need root permission)

$sudo vi /etc/ssh/sshd_config

AllowTcpForwarding yes
GatewayPorts yes


$sudo firewall-cmd --add-port=7004/udp [--permanent]
$sudo firewall-cmd --add-port=7004/tcp [--permanent]

Target PCB

$ssh -f -N -R 7004:127.0.0.1:22 -l user_PCX -p port PCX(ip/domain name)
This means open port 7004 on PCX forwarding to port 22, PCX will start to listen on port 7004.

Source PCA
$ssh PCX(ip/domain name) -l user_PCB -p 7004

Enjoy!



References:
[1] https://rootsaid.com/ssh-without-port-forwarding/
[2] https://linuxhint.com/ssh-port-forwarding-linux/
[3] https://dev.to/samuyi/the-how-to-of-ssh-port-forwarding-1f4e

Course of Deep Learning

Resources:
[1] Cutting-Edge Trends in Deep Learning and Recognition http://slazebni.cs.illinois.edu/spring17/
[2] Course Deep Learning https://nthu-datalab.github.io/ml/
[3] Colab https://medium.com/deepquestai/train-object-detection-ai-with-6-lines-of-code-6d087063f6ff

Review documents

Resources:

[1] https://www.visaoerevisao.com
[2] https://www.editage.com.br
[3] http://www.nativeenglish.com.br/ (word)

Ubuntu route (s)

ip route list

route

route add -net 10.0.0.0 netmask 255.0.0.0 gw 10.169.5.1



sudo route del -net 192.168.76.0/24
and
sudo route del -net 192.168.76.0 netmask 255.255.255.0


References:
[1] https://www.cyberciti.biz/faq/linux-route-add/

mySql Optimize date queries and inserts

High Level of use



DROP INDEX VENTAS_fecven_idx ON VENTAS

select * from VENTAS where date(fecven)='2019-03-09' #~2.81

select * from VENTAS where fecven >='2019-03-09 00:00:00' and fecven<'2019-03-10 00:00:00'  #~2.9


select * from VENTAS where fecven Between '2019-03-09 00:00:00' and '2019-03-10 00:00:00'  #~3.6


CREATE INDEX VENTAS_fecven_idx ON VENTAS (fecven)


select * from VENTAS where date(fecven)='2019-03-09' #~2.794

select * from VENTAS where fecven >='2019-03-09 00:00:00' and fecven<'2019-03-10 00:00:00'  #~0.265

select * from VENTAS where fecven Between '2019-03-09 00:00:00' and '2019-03-10 00:00:00'  #~0.261

CREATE INDEX MOVPRO_fecmov_idx ON MOVPRO (fecmov)
#change date(fecmov) between f1 and f2
#to         fecmov between f1 and f2  #implicit add 00:00:00

DROP INDEX MOVPRO_fecmov_idx ON MOVPRO


Setting mysql

SET GLOBAL bulk_insert_buffer_size = 1024 * 1024 * 128;
[mysqld]
bulk_insert_buffer_size=128M

References
[1] Insert https://dev.mysql.com/doc/refman/8.0/en/insert-optimization.html
[2] Amazon Best Practices https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_BestPractices.html

Linux Discovery ports

Mac
sudo lsof -iTCP -sTCP:LISTEN


Linux
List used ports 
$netstat -tulpn | grep LISTEN

tcp        0      0 127.0.0.1:5939          0.0.0.0:*               LISTEN      -                  
tcp        0      0 127.0.0.53:53           0.0.0.0:*               LISTEN      -                  
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      -                  
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      -                  
tcp6       0      0 :::80                   :::*                    LISTEN      -                  
tcp6       0      0 :::22                   :::*                    LISTEN      -                  
tcp6       0      0 ::1:631                 :::*                    LISTEN      -

List process that using port
You like to knows who is using port 80, then

$sudo lsof -i :80
apache2   965     root    4u  IPv6  26650      0t0  TCP *:http (LISTEN)
apache2 13794 www-data    4u  IPv6  26650      0t0  TCP *:http (LISTEN)
apache2 13795 www-data    4u  IPv6  26650      0t0  TCP *:http (LISTEN)
apache2 13796 www-data    4u  IPv6  26650      0t0  TCP *:http (LISTEN)
apache2 13797 www-data    4u  IPv6  26650      0t0  TCP *:http (LISTEN)
apache2 13798 www-data    4u  IPv6  26650      0t0  TCP *:http (LISTEN)


Second option

$sudo netstat -peanut | grep ":80"
tcp6       0      0 :::80                   :::*                    LISTEN      0          26650      965/apache2

Setting apache
$vi /etc/apache2/apache2.conf

#       /etc/apache2/
#       |-- apache2.conf
#       |       `--  ports.conf
#       |-- mods-enabled
#       |       |-- *.load
#       |       `-- *.conf
#       |-- conf-enabled
#       |       `-- *.conf
#       `-- sites-enabled
#               `-- *.conf

PostgreSQL 8.4 en CentOS

1) Deshabilitar repositorios

#vi /etc/yum.repos.d/CentOS-Base.repo

agregar la siguiente linea a [base] y [updates]
exclude=postgresql*

2) Añadir los repositorios de PostgreSQL 8.4
Descargar el rpm apropiado desde http://yum.pgsqlrpms.org/reporpms/repoview/pgdg-centos.html

#wget http://yum.pgsqlrpms.org/reporpms/8.4/pgdg-centos-8.4-2.noarch.rpm
#rpm -ivh pgdg-centos-8.4-2.noarch.rpm (este archivos es el que descargamos)

3) Instalar PostgreSQL

3.1 verifique version
#yum list postgresql*

#yum install postgresql postgresql-server

3.1 Error probable de dependencia a apr-util
#yum install apr-util
#yum install postgresql postgresql-server

4) Arrancar el servidor y habilitar conexiones remotas

#service postgresql initdb
#service postgresql start

5) Configurar Accesos en /var/lib/pgsql/data/
5.1 pg_hba.conf
host all all 0.0.0.0/0 trust   #no need password , use md5
5.2 postgresql.conf
listen_addresses='*'
port=5432
max_connections=100
superuser_reserved_connections=5

6) Reinicia servicio
#/etc/init.d/postgresql restart


Referencias
[0] Postgres 9.1 http://wiki.postgresql.org/wiki/YUM_Installation
[1] Auto Start/Stop http://www.michaelhinds.com/tech/linux/install-postgres.html
[2] http://www.ixavi.com/2010/01/instalar-postgresql-8-3-en-centos-desde-yum/

Linux root password reset

Mode 1:Recover mode

In recover mode try to remount and after that change password

mount -o remount,rw /
 
Mode 2: Using live

mkdir /mnt/recover
mount /dev/sda2 /mnt/recover
 
chroot /mnt/recover
 
passwd  #or
passwd user 
exit
umount /mnt/recover

Other way : Using files(for root or any user)
 
 /etc/passwd
 /etc/shadow
  
root:x:0:0:root:/root:/bin/bash
to
root::0:0:root:/root:/bin/bash 

References:

[1] http://www.microhowto.info/howto/reset_a_forgotten_root_password_using_a_live_distribution.html

[2] https://www.computersecuritystudent.com/UNIX/UBUNTU/1204/lesson5/index.html

Epson Drivers

Resources:
[1]  https://goo.gl/4vrWdC

Raspberry Resources

DOSBox and rpi-x86 will play DOS games and run Win31/Win95.

QEMU can be used to emulate an x86 PC but performance will be terrible.

Wine will not work because it does not translate binary data, only Windows API calls, the binaries are still incompatible.

This is a difficult problem to solve which is probably why ExaGear charge money for it.

Resources:
[1] Chart comparison all famous Arm processors https://www.loverpi.com/blogs/news/85588545-raspberry-pi-banana-pi-orange-pi-odroid-differences-and-chart
[2] Odroid vs other https://tudosobreraspberry.info/2017/08/comparacao-raspberry-pi-orange-pi-banana-pi-e-odroid/

[3] Raspberry Pi3 vs UDOO x86 https://www.youtube.com/watch?v=dJkHxDjFuNA
[4] Combine qemu and wine for run Windows applications https://github.com/AlbrechtL/RPi-QEMU-x86-wine
[5] https://www.kickstarter.com/projects/udoo/udoo-x86-the-most-powerful-maker-board-ever/?src=soc
[6] https://www.raspberrypi.org/forums/viewtopic.php?t=189198

[7] https://elchapuzasinformatico.com/2016/04/udoo-x86-10-veces-mas-potente-raspberry-pi-3-79e/
[8] https://www.redeszone.net/2016/05/20/udoo-x86-mini-ordenador-10-veces-mas-potente-raspberry-pi-3/
[9] https://www.anandtech.com/show/11978/macom-sells-off-appliedmicros-xgene-cpu-business
[1] Experimental comparison Raspberry and Orange https://raspberryparatorpes.net/rivales/raspberry-pi-vs-orange-pi-2017/

Ubuntu users

#adduser username

#usermod -aG sudo username

$su - username

$whoami

$sudo whoami   

Examples to use

$fdisk -l

$sudo fdisk -l

$sudo ls -l /root



mySql Optimization parameters or commands

Query

SHOW GLOBAL STATUS

SHOW VARIABLES LIKE '%size%';
SHOW GLOBAL VARIABLES LIKE '%size%';

Settings

SET GLOBAL join_buffer_size = 1024 * 1024 * 128 #128M

or

[mysqld]
join_buffer_size = 128M  #default ~256K

 

References:

[0] Compute memory http://mysqlcalculator.com/ 

[1] join_buffer_size https://dba.stackexchange.com/questions/74693/how-to-break-table-into-two-without-losing-performance 

[2] https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html

[3] Example tunning https://dba.stackexchange.com/questions/127862/tuning-mysql-variables-to-accommodate-high-load

[4] Query variables https://dev.mysql.com/doc/refman/8.0/en/show-variables.html

Sunat Servicios Web

Resources:
[1] Code perl http://cpan.dei.uc.pt/authors/id/G/GP/GPAREDES/SUNAT/SEE.pm

[2] http://orientacion.sunat.gob.pe/index.php/empresas-menu/comprobantes-de-pago-empresas/comprobantes-de-pago-electronicos-empresas/see-desde-los-sistemas-del-contribuyente/guias-manuales-y-servicios-web

JavaScript Frameworks Lecture

References:

[1] https://reactjs.org/
[2] https://www.w3schools.com/whatis/whatis_react.asp
[3] Repository https://github.com/facebook/react