This post presents circuit which produces a long up and down variation of the sound that similar to police siren. Circuit is based on two 555 timers which operates in...

Vim is a text editor that allows to create and modify text files via command line. Vim is an improved version of the old Unix Vi text editor. Vim provides...

The ncdu is a command line tool that enables to view and analyze disk space usage. This tool shows the disk space used by individual directories. By default, ncdu is...

This post presents circuit which detects darkness using light dependent resistor (LDR) and produces a beep alarm by piezo buzzer. Circuit is based on 555 timer in astable mode to...

This post presents circuit for blinking two LEDs alternatively using two BC547 transistors. This circuit is commonly called a flip flop LED flasher. Generally used in alarm systems to produce...

Nethogs is a command line tool that allows to monitor network bandwidth. Unlike most of the other tools, Nethogs groups bandwidth usage by process instead of per protocol or per...

WebSocket is a two-way communication protocol over a TCP. Websocat is a tool that enables to use WebSocket client or server from the command line. It can operate in client...

The hping3 is a command line tool that enables to analyze TCP/IP packets. The hping3 might be used as alternative to the ping command. The hping3 allows to send not...

The iftop is a command line tool that allows to monitor network bandwidth. This tool listens to the network traffic on specific interface and displays bandwidth usage in the table...

Nmap is a command line tool for network scanning and security auditing. Nmap allows to find what devices are connected to the network, what services are available and what operating...