which systemd subsystem replaces what?
Sysdig is open source, system-level exploration: capture system state and activity from a running Linux instance, then save, filter and analyze. Think of it as strace + tcpdump + lsof + awesome sauce. With a little Lua cherry on top.
A Middlebox Detection Tool
This free online service performs a deep analysis of the configuration of any SSL web server on the public Internet.
DevOps (a portmanteau of development and operations) is a software development method that stresses communication, collaboration and integration between software developers and information technology (IT) professionals.
Glances an Eye on your system