Here at System Code Geeks we know how much you love books about system administration; we are geeks ourselves. After all, a geek that respects himself should always have his face in a book, he has to keep up with the latest technologies and developments. For this reason, we have decided to distribute 4 of our books for free. You ...

Having our disk tidy and free of garbage occupies space is something we all want to do, but many times we don’t pay attention at large files that are taking up a considerable amount of space that could be useful for something else. In this example, we will see how to look for large files, just to be aware of ...

In the first tutorial of this series (PostgreSQL: Introduction and installation tutorial) we explained how to download a sample database and import it into our PostgreSQL server. This approach, although appropriate at the time, did not show how to create a database of our own from scratch – which is an essential skill that every database administrator (DBA) or developer ...

In our previous article we discussed how to free up disk space by vacuuming tables with frequent updates and deletes. Under the hood, this procedure also helps to improve the performance of other CRUD operations performed on those tables. In this tutorial we will explain how to optimize SELECT queries with WHERE clauses using indexes in PostgreSQL tables. 1. Introducing ...

In the previous tutorials of this series (“PostgreSQL: Introduction and installation” and “PostgreSQL commands and datatypes”) we explained how to load a sample database (World_db) into our PostgreSQL server and how to get help with both SQL and psql commands. In real-world scenarios, you will need to perform CRUD (Create, Read, Update, and Delete) operations on database tables all the ...

Screen is a window manager that allows to have several virtual terminals, several sessions and programs in text mode executing simultaneously in the same console. In this tutorial we will see how to use it. For this tutorial, Linux Mint 18 has been used. 1. Installation If you don’t have installed Screen, you can install it easily with apt-get: sudo ...

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In our previous post (PostgreSQL: Introduction and installation) we explained how to install and use a desktop and a web-based client to query a sample database we created and populated. We also introduced two basic commands to connect to a database (\c followed by the database name) and to quit (\q) the PostgreSQL prompt. PostgreSQL commands In this tutorial we ...

This example will show you how to create users in Linux, looking at the two different available commands: the default utility, useradd; and a script that acts as more friendly front-end for the default utility, which is named adduser. For this example, Linux Mint 17.03 has been used. 1. How users are organized The existing users of the system are ...

With all the Relational Database Management Systems (RDBMs) out there, it may be somewhat difficult to identify the best solution for your needs and to take an informed decision as to which one to choose. Thus, in this series we will provide an introduction to PostgreSQL and share some of the reasons why you may want to consider this solution ...

In this tutorial we will see how to add users to groups in Linux, looking at the different possibilities (existing or non-existing users), and taking into account also the different types of groups users can belong to (primary and secondary groups). For this example, Linux Mint 17.03 has been used. 1. How groups are organized Linux defines the groups in ...