Tuesday, January 31, 2017

Checking Debian Linux user password without logging into system

Checking Debian Linux user password without logging into system

Problem


Imagine situation when you need to check a user's password without logging into system and any traces of action. I had this situation when I was able:
  1. can execute sudo command;
  2. I needed to check password of root user from my machine. Also, I was not interested of  password change for root user.
 Note: you can check password for any user of your system.


Wednesday, January 25, 2017

Building Python 3.6 on Raspberry Pi 3 from sources (clean Debian)

Building Python 3.6 on Raspberry Pi 3 from sources (clean Debian)

 

1. Problem


By default clean Debian installation contains Python version 2.7.9 on my Debian (Raspbian GNU/Linux 8 (jessie)"). But we want more! We need Python 3.X, this tutorial shows you how to install Python version 3.6.0 .

Warning! Newer versions of Debian for Raspbery Pi have SSH disabled, so you need enable it by creating empty file with name ssh (Yes, just three letters. Yes, without extension) in /boot section of SD-card. This section also visible under Windows, so you will have no problems to do this.

Note: This is updated version of my previous tutorial Building Python 3.5 on Raspberry Pi 2 (Raspbian) which fixes issues with TLS/SSL support of compiled Python.


Tuesday, January 10, 2017

ACT LED Heartbeat for Raspberry Pi


All models of Raspberry Pi have ACT led. ACT led ON when SD card in use and OFF otherwise. 



Except of Raspberry Pi Zero, this devices uses opposite rules - ACT led is always ON and OFF only when SD card in use. This is useful because Raspberry Pi do not have PWD led and you can't understand is it powered on or not.

I like to tune ACT led to be in heartbeat mode, in this mode ACT led blinks twice than pause and again. This is useful because you can understand that device not just powered but also Linux kernel active. 

All that you need just add one line to config.txt file located in /boot partition of SD card.

Note: /boot partition have FAT fs, so you can do all operations directly from Windows OS just by editing text file.

From Linux (Raspbian for example) you need execute
$ sudo nano /boot/config.txt

Then navigate to the end of file and add line:

dtparam=act_led_trigger=heartbeat

That's all. After reboot your ACT led will act in heartbeat mode.

Enjoy!

Monday, January 9, 2017

Raspberry Pi Zero USB dongle (use SSH over USB cable like over Ethernet)

Raspberry Pi Zero USB dongle (use SSH over USB cable like over Ethernet)

About post

Imagine, if you will be able to use SSH (or even VNC) connection to your Raspberry Pi Zero using only USB cable without any hardware modifications. Amazing, isn't it?

You can find other instructions on Youtube requires hardware modification, but you can do this without soldering and so on.

All you need to follow these instructions.

Connecting to your Raspberry Pi without monitor, keyboard and mouse. Quick start.

Connecting to your Raspberry Pi without monitor, keyboard and mouse. Quick start.

 About article

Imagine if you want your own Linux server for debugging and testing purpose. Of course you can buy VPS, but this is can be a little bit expensive for some cases. In this case you can use just Raspberry Pi which able to run Apache, Nginx, PostgreSQL.

So you need your RPi + PSU (Power Supply Unit) and RTC (preferred). 

But you need to configure your RPi, so you need keyboard, monitor, mouse, HDMI adapters and so on. Right? Wrong! Your do not need anything except RPi + PSU + RTC (optional).