How a parenthesis in Linux process names silently breaks most /proc stat parsers

Developer Maneshwar, while building a terminal process monitor called ratatop, uncovered a widespread parsing bug in how tools read Linux's /proc/[pid]/stat file. The file is space-separated, but the process name field can itself contain spaces and parentheses, causing naive whitespace splits to misalign every subsequent field. This means tools relying on simple splitting may silently read wrong values for CPU time, memory, and thread count without any crash or error. The correct fix is to locate the last closing parenthesis using rfind, isolating the name before splitting the remainder of the line. Maneshwar also notes that CPU percentage calculations carry a separate design choice: whether to measure against a single core or the total machine capacity, a distinction that can produce eightfold differences in displayed values.