постраничная основа (by-page basis)
Входные файлы (Input files)
The input files being examined shall be text files. If standard
output is a terminal, standard error shall be used to read
commands from the user. If standard output is a terminal,
standard error is not readable, and command input is needed, more
may attempt to obtain user commands from the controlling terminal
(for example, /dev/tty); otherwise, more shall terminate with an
error indicating that it was unable to read user commands. If
standard output is not a terminal, no error shall result if
standard error cannot be opened for reading.
