Understanding Linux Man Page Section Numbers: What sleep(3) and read(2) Actually Mean

Summary

The article explains the meaning of numbers in Linux man page titles (like sleep(3) or read(2)), which indicate manual sections. The author discovered this after a code review comment pointed out that 'man 2 basename' was incorrect since basename is a library call, not a system call. The man(1) page reveals that section 1 is for executable programs, section 2 for system calls, section 3 for library calls, and so on, clarifying that basename(3) is the correct reference as it's a libc library function.