Bash Patterns and Regular Expressions

Course details

Pattern matching allows you to create a script that can act on pieces of data if it matches a specific pattern. This makes it possible to script automation into a system process. In this course, learn how to use pattern matching in a Bash script using globs, extended globs, brace expansion, and regular expressions (regex). Throughout this course, Grant McWilliams covers the differences between basic and extended regexes and delves into using extended regexes in bash conditional statements, grep, sed, and AWK.

Learning objectives
What are globs and extended globs?
How locale affects searches
Making extended globs persistent
Comparing extended globs with regular expressions (regexes)
Using brace expansion for patterns
Working with extended regexes
Using sed
Regexes in AWK

Concepts

Introduction

Use Bash to pull data in seconds
What you should know

Shell Globs

What are globs
Shell expansion order
Wildcards
Character sets
The effect of locale on searches
Character classes
Shell globbing options

Shell Extended Globbing

What are extended globs
Why you should use extended globs
Make extended globs persistent
Getting started with extended globs
Pattern matching with extended globs
Using extended globs with commands
Comparing extended globs with regular expressions

Shell Brace Expansion

What is brace expansion
Using brace expansion for patterns

Introduction to Regular Expressions

What are regular expressions
Why aren't regexes consistent
Basic vs. Extended Regular Expressions
Regex support in command line tools
Matching characters and words
Specifying occurrences
Alternation and grouping
Back references and subexpressions

Use Bash Extended Regexes

Regexes in if conditionals
Using BASH REMATCH
Challenge - Regex to find credit card numbers
Solution - Regex to find credit card numbers

Grep EREs and PCREs

Using regular expressions with grep
Perl compatible regexes with grep
Performance optimizing grep searches
Challenge - Create a regex to find telephone numbers
Solution - Create a regex to find telephone numbers

Use sed Regexes

Using sed
Using extended regexes in sed
Challenge - Create a regex to find IPv4 addresses
Solution - Create a regex to find IPv4 addresses

Use AWK Extended Regexes

Using regexes in AWK
Pattern matching differences in AWK

Conclusion

Next steps