Major Open source (Linux) Applications

Linux is embedded in:
Roku
Chromebooks
Kindle
Android Phones
PS4 runs Orbis OS, a modified version of FreeBSD that’s similar to Linux

ESXi

Factory autmation

Raspberry Pi

Mars Rovers

Linux Firewalls:
Smoothwall
PfSense
Monowall

Major open source applications:
Apache
Libre Office
Samba
NFS
MySQL
Postfix
Firefx
OpenOffice
THunderbird
Chromium
Webmin
SSH Clients
Mobile Browsers
C
C++
PHP
Perl
Shell
Java