/usr/bin/top

Security researcher Nicolas Seriot documents how /usr/bin/top, the macOS system monitor, ends up performing an unnecessary Fibonacci-style recursive computation through terminal capability string parsing, meaning the utility wastes CPU cycles every time it runs. The write-up walks through the terminfo parsing chain that triggers the hidden workload. Developers are sharing the finding as a striking example of obscure, parasitic computation lurking in everyday Unix tools.

A researcher at seriot.ch has documented how a terminfo configuration can force /usr/bin/top, the standard Unix process monitor, to carry out a parasitic Fibonacci computation as a hidden side effect. The write-up explains the mechanism and its performance implications, and it is drawing attention from developers surprised that a routine terminal database entry can trigger unexpected CPU work inside a core system utility.