Week 6

Metacharacters for grep(1), egrep(1):

	. (dot)
	[] square brackets
	\{\} \{n\} \{m,n\} \{,n\}==(does not work) \{n,\}
	\<\> match a word.
	\
	^
	$
	*
	?
	+
	\(\) \(gsdjgk\)\(fkjgsdfk\) recall using  $1 $2 
	|

Description of above with examples. 

Usage of grep(1).

				Metacharacters

. --> any single character except newline

* ---> quantifier character, 0 or more occurrences of the previous
		character (or RE)

	A* 

	.* 

[]  --> same meaning as shell, cannot use !

	[ABC] --> match one character A or B or C
	[^1234567890] --> match any non-digit character
	[A-M] --> one character - must be A or B  etc upto M

? ---> 0 or one occurrence of the prev. character. 

+ ---> (egrep only) 1 or more occur. of the prev. RE/character

\. --> match a . literally
\?  --> match ? literally
\\ --> match a \
^  --> anchor match the beginning of 
$ --> anchor match the end.