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.
First appearing in Version 4 Unix, grep was created by Ken Thompson as a standalone application adapted from the regular expression parser he had written for ed (which he also created). In ed, the command g/re/p would print all lines matching a previously defined pattern.