Number in man page titles e.g. sleep(3) (lalitm.com)

The post explains what the trailing numbers in Linux man-page titles (e.g., sleep(3), read(2)) mean, pointing to the man(1) manual’s section numbering: section 2 covers system calls and section 3 covers library calls. It also notes that additional letter suffixes like “p” (POSIX) or “x” (X/Open or related documentation) may appear. The author shares that they were previously unsure why these numbers existed, but clarifies how to interpret them when reading man pages.