chmod(1p), find(1p)
The Base Definitions volume of POSIX.1‐2017, Section 7.3.2,
LC_COLLATE, Section 4.5, File Access Permissions, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines,
sys_stat.h(0p)
The System Interfaces volume of POSIX.1‐2017, fstatat(3p)