[ Thanks to An Anonymous Reader for
this link. ]
“How do I use the Grep command with regular expressions
under Linux operating systems?“Linux comes with GNU grep, which supports extended regular
expressions. GNU grep is the default on all Linux systems. The grep
command is used to locate information stored anywhere on your
server or workstation. Regular Expressions is nothing but a pattern
to match for each input line. A pattern is a sequence of
characters.“Following all are examples of pattern:
^w1 w1|w2 [^ ]