LUKI NOTES

An SSH key allows you to establish a secure connection between your computer and a remote server. This type of connection run by generating an SSH key in your local computer (or remote computer, keep private and public key in local computer, then store the public key in remote server. In Ubuntu, you can use this command: $ ssh-keygen -t rsa -C "lukibsubekti@gmail.com"

Git is a popular version control application nowadays. Recently I have created a note about its differences with SVN and how to use it in Eclipse . There are many Git client tools. But I just want to show how to use Netbeans built-in Git tools. It makes the development process easier because it has been integrated with the IDE. Create Remote Git Repository We need a remote Git repository so everyone can store or receive any revision or updated files through the networks. We can set up our own Git server or use a public Git server like Github . In this note, I use Github. 1. Create an account in Github and create an empty Git repository Create an empty public repository in Github 2. Get the remote repository link Your Github Repository URL Create a New Project in Netbeans and Create Local Git Repository After we have a remote Git repository, we can create a project stored in the remote repository. We also need to create a local repository before we can push

A self-signed SSL Certificate can be used if you want to make a secure connection to a server by encrypting the data like the HTTPS connection. We can utilize OpenSSL to generate the key and certificate. We can run  $ sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /path/to/yourkey.key -out /path/to/yourcert.crt to generate the key and certificate files.  Some important parameters are as follows: req : This specifies a subcommand for X.509 certificate signing request (CSR) management. X.509 is a public key infrastructure standard that SSL adheres to for its key and certificate management. Since we are wanting to create a new X.509 certificate, this is what we want. -x509 : This option specifies that we want to make a self-signed certificate file instead of generating a certificate request. -nodes : This option tells OpenSSL that we do not wish to secure our key file with a passphrase. Having a password-protected key file would get in the way of Apache

In Ubuntu 14.04, PostgreSQL repository isn't listed by default. We must add the record first. Run $ nano /etc/apt/sources.list.d/pgdg.list to add repository list file Add deb http://apt.postgresql.org/pub/repos/apt/ trusty -pgdg main in the file Run $ wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | \ sudo apt-key add - Run $ sudo apt-get update then $ sudo apt-get install postgresql-9.4 For administrator we can install pgadmin3 $ sudo apt-get install pgadmin3 For client tools we can install postgresql-client $ sudo apt-get install postgresql-client

When you download a file from a website, sometime the website also provide some codes of MD5 sum result to check file integrity after downloading. MD5 sum result can be generated using this command. $ md5sum download.file Then you can compare your result with code provided by the website. Next, to verify authenticity via GPG, use this following steps. - download the public key - download the authenticity key - run: $ gpg --import publickey.asc - run: $ gpg --verify authkey.asc downloaded.file

.tar.gz files are gzip-compressed .bz2 files are compressed with bzip2 Extract tar.gz: $ tar -xzf file.tar.gz Extract bz2: $ tar -xjf file.tar.bz2 -v to see files being extracted