Anchors do not match the characters at all. Anchors are used to match the characters at certain positions, such as at the beginning or end of a line. If the anchors are not used in the proper position, either at the beginning or end of a regular expression, they do not act as anchors. The ^ and $ are two metacharacters that are known as anchors in regular expressions.
- Title Page
- Copyright and Credits
- Dedication
- Packt Upsell
- Contributors
- Preface
- Getting Started with AWK Programming
- AWK programming language overview
- Getting started with AWK
- AWK standard options
- Summary
- Working with Regular Expressions
- Introduction to regular expressions
- Basic regular expression construct
- Understanding regular expression metacharacters
- Precedence in regular expressions
- GAWK-specific regular expression operators
- Case-sensitive matching
- Escape sequences
- Summary
- AWK Variables and Constants
- Working with Arrays in AWK
- Printing Output in AWK
- The print statement
- Role of output separator in print statement
- Pretty printing with the printf statement
- Escape sequences for special character printing
- Different format control characters in the format specifier
- Format specification modifiers
- Printing with fixed column width 
- Using the minus modifier (-) for left justification
- Printing with fixed width – right justified
- Using hash modifier (#)
- Using plus modifier (+) for prefixing with sign/symbol
- Printing with prefix sign/symbol
- Dot precision as modifier
- Positional modifier using integer constant followed by $ (N$):
- Redirecting output to file
- Summary
- AWK Expressions
- AWK variables and constants
- Arithmetic expressions using binary operators
- Assignment expressions
- Increment and decrement expressions
- Relational expressions
- Logical or Boolean expressions
- Ternary expressions
- Unary expressions
- Exponential expressions
- String concatenation
- Regular expression operators
- Operators' Precedence
- Summary
- AWK Control Flow Statements
- AWK Functions
- Built-in functions
- Arithmetic functions
- String functions
- The index (str, sub) function
- The length ( string ) function
- The split (str, arr, regex) function
- The substr (str, start, [ length ]) function
- The sub (regex, replacement, string) function
- The gsub (regex, replacement, string) function
- The gensub (regex, replacement, occurrence, [ string ]) function
- The match (string, regex) function
- The tolower (string) function
- The toupper (string) function
- The sprintf (format, expression) function
- The strtonum (string) function
- Input/output functions
- The time function
- Bit-manipulating functions
- User-defined functions
- Summary
- Built-in functions
- GNU's Implementation of AWK – GAWK (GNU AWK)
- Practical Implementation of AWK
- Working with one-liners for text processing and pattern matching with AWK
- Selective printing of lines with AWK
- Modifying line spacing in a file with AWK
- Numbering and calculations with AWK
- Selective deletion of certain lines in a file with AWK
- String operation on selected lines with AWK
- Array creation with AWK one-liner
- Text conversion and substitution in files with AWK
- One-liners for system administrators
- Use case examples of pattern matching using AWK
- Parsing web server (Apache/Nginx) log files
- Understanding the Apache combined log format
- Using AWK for processing different log fields 
- Identifying problems with the running website
- Printing the top 10 request IP addresses with their GeoIP information
- Counting and printing unique visits to a website
- Real-time IP address lookup for requests
- Converting text to HTML table
- Converting decimal to binary
- Renaming files in a directory with AWK
- Printing a generated sequence of numbers in a specified columnate format
- Transposing a matrix
- Processing multiple files using AWK
- Parsing web server (Apache/Nginx) log files
- Summary
- Further reading
- Working with one-liners for text processing and pattern matching with AWK
Anchors
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