постраничная основа (by-page basis)
Смотри также (See also)
Chapter 2, Shell Command Language, ctags(1p), ed(1p), ex(1p),
vi(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 9.2, Regular Expression General
Requirements, Section 9.3, Basic Regular Expressions, Section
12.2, Utility Syntax Guidelines
