линии печати, соответствующие шаблонам (print lines that match patterns)
Описание (Description)
grep searches for PATTERNS in each FILE. PATTERNS is one or more
patterns separated by newline characters, and grep prints each
line that matches a pattern. Typically PATTERNS should be quoted
when grep is used in a shell command.
A FILE of '-' stands for standard input. If no FILE is given,
recursive searches examine the working directory, and
nonrecursive searches read standard input.
