Ubuntu Reconfigure Locale

When the default locale is not setup properly, following warning displayed in the ubuntu terminal

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
	LANGUAGE = (unset),
	LC_ALL = (unset),
	LC_CTYPE = "en_AU.UTF-8",
	LANG = "en_US.UTF-8"
    are supported and installed on your system.


locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory

To setup locale

sudo dpkg-reconfigure locales
sudo locale-gen

How to Extract the Private and Public Key From pfx File

Converting Private Key

// Convert Private RSA Key PEM 
openssl pkcs12 -in {pfx_file_name}.pfx -nocerts -nodes -passin pass:{password} | openssl rsa -out privkey.pem 

// Convert Private RSA Key to Private PEM 
openssl pkcs8 -topk8 -inform PEM -in privkey.pem -outform PEM -nocrypt > private.pem

Converting Public Certificate Pem

openssl pkcs12 -in {pfx_file_name}.pfx -clcerts -nokeys -passin pass:{password} -out publicCert.pem

Convert to Public Key

openssl pkcs12 -in {pfx_file_name}.pfx -clcerts -nokeys -passin pass:{password} | openssl x509 -pubkey -noout | ssh-keygen -f /dev/stdin -i -m PKCS8 > public_key

An alternative way 

// Exports all keys
openssl pkcs12 -in {pfx_file_name}.pfx -nocerts -nodes -passin pass:{password} -out exported.key
// Export Private RSA Key PEM 
openssl rsa -in exported.key -out privkey.pem
// Convert Private RSA Key to Private PEM 
openssl pkcs8 -topk8 -inform PEM -in privkey.pem -outform PEM -nocrypt > private.pem

// Export Public key
openssl rsa -in exported.key -pubout -out publicCert.pem

Install zsh

apt install zsh
chsh -s /bin/zsh root
chsh -s /bin/zsh {username}

exit and login again

Go to oh-my-zsh website

Install on-my-zsh by following

sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"

change themes in ~/.zshrc, e.g. philips, or schminitz

Turn off MySQL Password Validate

Turn off MySQL Password Validate for a development environment

Login to the mysql server as root

mysql -h localhost -u root -p

Run the following sql command

uninstall plugin validate_password;

Turn on the plugin

INSTALL PLUGIN validate_password SONAME 'validate_password.so';

Updated the plugin policy level by adding following line in `/etc/mysql/my.cnf`

validate_password_policy=LOW;

MySQL 8 Homebrew installation

Just in case `mysql_secure_installation` doesn’t work after a new mysql 8 installation.

Install MySQL

brew install mysql

Stop it

brew services stop mysql

Start the safe mode

/usr/local/Cellar/mysql/8.0.11/bin/mysqld_safe

Login and skip password

mysql -u root --skip-password

Change password and exit

ALTER USER 'root'@'localhost' IDENTIFIED BY 'a-new-password';
exit;

Stop safe mode mysql

mysql.server stop

Start mysql

Create `~/.my.cnf` with following content

[client]
host = localhost
user = root
password = a-new-password

Docker Ubuntu 18.04 Installation

Install Docker CE

sudo apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    software-properties-common

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

sudo apt-key fingerprint 0EBFCD88

$ sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"

sudo apt-get update

sudo apt-get install docker-ce

#Allow user run docker with `sudo`
sudo usermod -a -G docker {username}

https://docs.docker.com/install/linux/docker-ce/ubuntu/#install-docker-ce-1

Install Docker Composer

sudo curl -L https://github.com/docker/compose/releases/download/1.22.0-rc2/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose


sudo chmod +x /usr/local/bin/docker-compose

https://docs.docker.com/compose/install/

https://github.com/docker/compose/releases

Yesod Handbook

Install Stack

brew update
brew install haskell-stack

Init Yesod project

stack new {project-name} yesod-sqlite && cd {project-name}

Install Yesod command line tool

stack install yesod-bin --install-ghc

Build

stack build

Launch devel server

stack exec -- yesod devel

MongoDB Management

Create a new database

use {databases-name}

Check current database

db

Show database

show dbs

The empty database won’t be displayed (at least one document is inserted)

In MongoDB default database is test. If you didn’t create any database, then collections will be stored in test database.

Drop database

db.dropDatabase()

Collections

Create a collection

db.createCollection("a-collection")

Show collections

show collections

Mongodb create a collection automatically when insert a document.

Drop collection

db.mycollection.drop()

Backup

mongodump -d {database-name} -o {dump-pass}

Restore for bson

mongorestore -d {database-name} -c {collection-name} {dump-pass}/{collection-name}.bson