"Following is a summary of some of the major features
of regular expressions.
"1. Supported by Linux/UNIX Utilities
Most commands will support at least the basic aspects of regular
expressions. What this means is that as a tool enhancement regular
expressions have important implications are are worth your time in
learning. Three major utilities demonstrate the importance of
a. grep – a line parsing tool that is based on regular
b. awk – a filed parsing tool based on matching text and
using regular expressions
c. sed – a stream editor which facilitates the modification
of text streams
"Experience with these three tools or utilities is critical in
the building of shell scripts.
"2. Reduces Evaluation Times
Because the use of regular expressions provides the ability to
perform multiple tasks at one time, regular expressions save time
and resources on a server. Instead of performing many passes over
the same text in order to achieve one goal at a time, you can
achieve many goals using regular expressions."