outlet - an opening that permits escape or release; he blocked the way out; the canyon had only one issue. exit, way out, issue. opening - a vacant or unobstructed space that is man-made; they left a small opening for the cat at the bottom of the door.
Differences between grep, pgrep, egrep, and fgrep (Linux): grep grep is an acronym that stands for Global Regular Expressions Print. grep is a program which scans a specified file or files line by line, returning lines that contain a pattern. A pattern is an expression that specifies a set of strings by interpreting characters as meta-characters.
does not work. In fact, grep considers file to be the pattern, and then searches standard input for the word file.. If you type the above command, it will wait for you to type control-D before it ends, as it is reading standard input. You see, grep considers the hyphen as an indication of an option.