Category: Linux

Supervisord
supervisord is a program that allows you to monitor and control processes. supervisord runs processes as its sub-process and can restart a process if it crashes.

supervisord is the server. supervisorctl is the client program.

You can find more info at

supervisorctl
How to Install Supervisord on CentOS 7

To install on CentOS run
```
yum -y install supervisor
```
On Ubuntu/Debian
```
apt install -y supervisor
```
Config files are stored in
```
/etc/supervisor/
```
Your own application configurations at
```
/etc/supervisor/conf.d/
```
some useful commands
```
supervisorctl reread
supervisorctl update
```
To restart all services, run
```
supervisorctl restart all
```
Start x11vnc with supervisord

See autostart
February 6, 2018
openssl
View SSL certificate details
```
openssl x509 -in ssl.crt -text -noout
```
To get SSL certificate details of a web site
```
timeout 5 echo QUIT | openssl s_client -connect serverok.in:443 2>&1 | openssl x509 -noout -text
```
February 6, 2018
Dedicated Server Providers
Here are some dedicated server providers. If you need any recommendations or found a service provider that you think useful, contact me at admin@serverok.in

Value For Money
- https://www.ovh.com
- https://www.hetzner.com
Dedicated Servers
- http://www.leaseweb.com – relable, used by many file hosts. Now they have USA servers too (acquired servint.net)
- http://www.tailormadeservers.com
- http://www.reliablesite.net
- https://phoenixnap.com/servers/dedicated
- https://www.limestonenetworks.com/pricing/bare-metal-cloud – hourly pricing. $100 trail for 3 months.
- https://www.interserver.net/dedicated/
- https://www.servermania.com/dedicated-servers-hosting.htm
Cheap Dedicated Servers

These servers are very cheap. You can’t get a decent VPS for this price. Only use them for personal sites. Also make sure you take regular backups.
- https://www.kimsufi.com
- https://www.soyoustart.com
- https://oneprovider.com/ – Owned by online.net, they have some very cheap servers.
- https://www.wholesaleinternet.net
- https://www.nocix.net
See list of Cloud Hosting Providers
February 4, 2018

PostgreSQL

psql commands

\l	List databases
\l+	List databases
\c DB_NAME	connect to a database
\du	list users
\dt	list tables
\d TABLE_NAME	describe a table
\dn+	List of schemas

To install PostgreSQL on Ubuntu/Debian, run

apt-get install -y postgresql

Start it with

service postgresql start

By default user “postgres” have full access on PostgreSQL. To create a user, run

su postgres
createuser -P USERNAME

To create a database, run

createdb -T template0 -E UTF8 -O USERNAME DBNAME

You can see help with

postgres@ok-vm:~$ createdb --help
createdb creates a PostgreSQL database.

Usage:
  createdb [OPTION]... [DBNAME] [DESCRIPTION]

Options:
  -D, --tablespace=TABLESPACE  default tablespace for the database
  -e, --echo                   show the commands being sent to the server
  -E, --encoding=ENCODING      encoding for the database
  -l, --locale=LOCALE          locale settings for the database
      --lc-collate=LOCALE      LC_COLLATE setting for the database
      --lc-ctype=LOCALE        LC_CTYPE setting for the database
  -O, --owner=OWNER            database user to own the new database
  -T, --template=TEMPLATE      template database to copy
  -V, --version                output version information, then exit
  -?, --help                   show this help, then exit

Connection options:
  -h, --host=HOSTNAME          database server host or socket directory
  -p, --port=PORT              database server port
  -U, --username=USERNAME      user name to connect as
  -w, --no-password            never prompt for password
  -W, --password               force password prompt
  --maintenance-db=DBNAME      alternate maintenance database

By default, a database with the same name as the current user is created.

Report bugs to <pgsql-bugs@postgresql.org>.
postgres@ok-vm:~$

run psql

sudo -u postgres psql

Run a command in psql

sudo -u postgres psql -c "\du"

List all tables in a database

sudo -u postgres psql -c "\c serverok_db" -c "\dt"

List postgresql extensions

sudo -u postgres psql -c "SELECT * FROM pg_available_extensions;"

Extensions are stored in folder /usr/share/postgresql/16/extension/

February 4, 2018

Install x2go Server in Ubuntu 16.04
To install x2Go server in Ubuntu, run
```
add-apt-repository ppa:x2go/stable
apt-get update
apt-get -y install x2goserver x2goserver-xsession
```
if you don’t have xfce, install it with
```
apt -y install xfce4
```
See x2go, add-apt-repository
February 2, 2018

no matching host key type found. Their offer: ssh-dss

When i try connect to a server, i get error

root@ok:~# ssh n1eb4141@50.62.71.1
Unable to negotiate with 50.62.71.1 port 22: no matching host key type found. Their offer: ssh-dss
root@ok:~#

Same happens with scp

root@ok:~# scp n1eb4141@50.62.71.1:/var/chroot/home/content/83/13319983/html.tar .
Unable to negotiate with 50.62.71.1 port 22: no matching host key type found. Their offer: ssh-dss
root@ok:~#

To fix this, add -oHostKeyAlgorithms=+ssh-dss to the command.

Example

ssh -oHostKeyAlgorithms=+ssh-dss n1eb4141@50.62.71.1

To list all supported ciphers, run

ssh -Q cipher

You can use -c option to change chiper.

ssh -c aes128-cbc n1eb4141@50.62.71.1

February 2, 2018

ioncube

How To Install ionCube on Ubuntu 20.04
Install ionCube on Ubuntu 18.04
Install ionCube on Debian 8
Install ionCube on Debian 9
Install ionCube Loader on CentOS 7
Install ioncube on CentOS Plesk Server

February 1, 2018

Install ioncube on Debian 8

To install ioncube Debian 8, first download the ioncube loader from

http://www.ioncube.com/loaders.php

cd /usr/local/src
wget https://downloads.ioncube.com/loader_downloads/ioncube_loaders_lin_x86-64.tar.gz
tar xvf ioncube_loaders_lin_x86-64.tar.gz
cd ioncube/

This folder have loader for several PHP versions, find the PHP version you have with command

php -v

By default Debian 8 come with PHP 5.6. The file you need to use for PHP 5.6 is ioncube_loader_lin_5.6.so

You need to copy this file to PHP extension directory. To find this, run

# php -i | grep extension_dir
extension_dir => /usr/lib/php5/20131226 => /usr/lib/php5/20131226
#

Lets copy ioncube loader file to extension diretcory

cp /usr/local/src/ioncube/ioncube_loader_lin_5.6.so /usr/lib/php5/20131226

create file

echo "zend_extension=ioncube_loader_lin_5.6.so" > /etc/php5/apache2/conf.d/01-ioncube.ini
ln -s /etc/php5/apache2/conf.d/01-ioncube.ini /etc/php5/cli/conf.d/01-ioncube.ini

Restart Apache web server

service apache2 restart

You can verify ioncube module installed with

root@myterrarium-vm:~# php -m | grep ion
ionCube Loader
Reflection
session
the ionCube PHP Loader (enabled) + Intrusion Protection from ioncube24.com (unconfigured)
root@myterrarium-vm:~#

See ioncube | Install ionCube on Debian 9

February 1, 2018

pip

Install pip

On CentOS

wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py

On Ubuntu

apt install python-pip

On Ubuntu, python3

apt install python3-pip

Install a python module from github using pip

cd /opt/bench
git clone https://github.com/frappe/bench bench-repo

Now run

pip install -e bench-repo

Install modules from requirments.txt

pip install -r requirements.txt

To create requirements.txt file, run

pip freeze > requirements.txt

January 30, 2018

usermod
- Lock User Account in Linux
- How to change home directory of a Linux user
On CentOS, the wheel group allows users in this group to run commands as user root with sudo.

To add a user to the wheel group, run
```
usermod -aG wheel USERNAME
```
On Ubuntu/Debian, use
```
usermod -aG sudo USERNAME
```
Remove a User from Group
```
deluser USERNAME GROUP
```
Example
```
root@ip-172-31-56-4:~# deluser designware sudo
Removing user `designware' from group `sudo' ...
Done.
root@ip-172-31-56-4:~# 
```
Here we remove user designware from group sudo.

To remove a user from all secondary groups, run
```
usermod -G "" USERNAME
```
Change user shell

To disable SSH login, run
```
usermod -s /sbin/nologin USERNAME
```
For example
```
usermod -s /sbin/nologin mysql
```
useradd
January 30, 2018

Install Node.js on CentOS Server

You can find latest version of Node.js at

https://nodejs.org/en/

To install Node.js on CentOS 7/8

Add node.js repository

NodeJS 12.x

curl -sL https://rpm.nodesource.com/setup_12.x | bash -

NodeJS 11.x

curl -sL https://rpm.nodesource.com/setup_11.x | bash -

NodeJS 10.x

curl -sL https://rpm.nodesource.com/setup_10.x | bash -

NodeJS 8.x

curl -sL https://rpm.nodesource.com/setup_8.x | bash -

NodeJS 6.x

curl -sL https://rpm.nodesource.com/setup_6.x | bash -

Install node.js with

yum -y install nodejs

For npm to install native modules, install dev tools

yum install gcc-c++ make

yum groupinstall 'Development Tools'

See Node.Js

January 30, 2018

lftp
Download files
- Download all files from FTP server using lftp
- Download all files from SFTP server using lftp
Upload files
- Upload all files to FTP server using lftp
lftp Errors
Connect to a server
```
lftp -u USER,PASSWORD SERVER_IP
```
Disable SSL
```
set ftp:ssl-allow false
set ssl:verify-certificate no
```
Enable Active FTP mode
```
set ftp:passive-mode off
```
January 29, 2018

Category: Linux

Value For Money

Dedicated Servers

Cheap Dedicated Servers

Change user shell

Download files

Upload files

lftp Errors