Regular expressions

A regular expression is a pattern enclosed in forward slashes. A regular expression can contain meta-characters. If the pattern matches any string in the record, then the condition is true and any associated action, if mentioned, will be executed. If no action is specified, then the record is simply printed on the screen.

Meta-characters used in awk regular expressions are as follows:

Meta-character

What it does

.

A single character is matched

*

Zero or more characters are matched

^

The beginning of the string is matched

$

The end of the string is matched

+

One or more of the characters are matched

?

Zero or one of the characters are matched

[ABC]

Any one character in the ...

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