Unix Third Edition: Visual Quickstart Guide

Using Regular Expressions with grep

In addition to using grep to search for simple text strings, you can also use grep to search for regular expressions. Regular expressions are kind of like fancy wildcards, where you use a symbol to represent a character, number, or other symbol. With regular expressions, you can search for different parts of files, such as the end of a line or a text string next to another specified text string. Table 6.1 lists some of the more common regular expressions.

Table 6.1. Regular Expressions, Examples, and Explanations

REGULAR EXPRESSION	FUNCTION	EXAMPLE	EXPLANATION
.	Matches any character	grep b.rry	This finds all instances of “berry” or “barry.”
*	Matches zero or more instances of the preceding item, so a*b would find “b” ...