Tutorials Index Page 1

intermediate

Different ways to revert git repository commit

To undo last commit not pushed try: git reset --soft HEAD~1. To undo last commit pushed use: git revert HEAD~1. Check this tutorial for more examples!

beginner

ethereum: geth how to change the database (chaindata) directory?

Geth now support the datadir parameter, example: geth --datadir "/mnt/external"

How to find the mime type of a file in Python?

Here are some example on how to guess the mime type of a file using python. The first example uses the filename only and the second example opens the file to guess the mime type.

beginner

PostgreSQL: Update query for JSONB columns with examples

PostgreSQL 9.5 added the type JSONB, which supports json as datatype. Here we show an example on how to perform an UPDATE on a jsonb type using postgresql. If you want to override the whole dict, just send the json between single quotes. check here for some example queries.

intermediate

How to move luks encrypted disk to smaller SSD drive (using LVM)

In this tutorial, we are going to move a linux encrypted disk to a new one. In particular, we are going to move from an old hard drive to a brand new SSD (but smaller). This tutorial also works for moving encryted disk to a bigger disk.

flask example with POST API endpoint

In this tutorial, we are going to see how to create an API endpoint using flask. The endpoint will only accept POST request and it will use content-type application/json. Learn here how to create a minimal api rest with flask and python.

How to use setup Epson L355 on Ubuntu 18.04

Steps to install Epson L355 on Ubuntu 18.04. You will need to download the official drivers from epson.net (deb file). Use dpkg to install epson-inkjet-printer-201207w_1.0.0-1lsb3.2_amd64.deb. Finally, use the wizard as always. Check here for full details and epson Ubuntu 18.04 drivers.

Using python SQLAlchemy with SQLlite3 tutorial

Learn here how to use SQLIte3 with SQLAlchemy step by step. First, we are going to define some models and then we will see how to connect and make some queries. We are going to learn about the Unit of Work pattern, which is a very important concept on sqlalchemy.

beginner

How to update the Go version

Steps to update go lang to the latest version. Remove your current go and then Go to the [downloads](https://golang.org/dl/) page and download the binary release. finally install it following the steps in this guide.

intermediate

Fast bulk insert with sqlalchemy

SQLAlchemy has some ways to do fask bulk inserts into the database. With this tutorial you will learn how to insert a large number of rows in bulk, using dictionaries or objects.