линии печати, соответствующие шаблонам (print lines that match patterns)
Статус выхода (Exit)
Normally the exit status is 0 if a line is selected, 1 if no
lines were selected, and 2 if an error occurred. However, if the
-q or --quiet or --silent is used and a line is selected, the
exit status is 0 even if an error occurred.
