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.
In the Perl programming language, grep is the name of the built-in function that finds elements in a list that satisfy a certain property. This higher-order function is typically named filter in functional programming languages. The pcregrep command is an implementation of grep that uses Perl regular expression syntax. Similar functionality can be invoked in the GNU version of grep with the -P flag. Ports of grep (within Cygwin and GnuWin32, for example) also run under Microsoft Windows. Some versions of Windows feature the similar qgrep or Findstr command.