The kernel supports performance analysis with built-in tools via the Linux performance counters subsystem. perf is easy to use and offers a detailed view of performance data.
Before the web as we know it existed, Usenet performed the same tasks now done by web forums and social networks. Despite its declining popularity, Usenet is still employed to publish articles, sustain mailing lists, and even upload files.
Bash is known for admin utilities and text manipulation tools, but the venerable command shell included with most Linux systems also has some powerful commands for manipulating binary data.
Writing computer-related tutorials, documentation, articles, etc., is virtually impossible without a good utility for taking screenshots -- and Shutter has all the features you could possible need.
