Perl Maven
This book is 100% complete
Completed on 2018-05-05
About the Book
The book is based on the material of the most popular Perl Tutorial found on the Perl Maven site. Its creation was supported by 100 people in a crowdfunding campaign in March 2018. The book covers the basics of the Perl programming language. It introduces all the concepts you need to know to put together a Perl script or take apart one written by someone else.
The book explains both the plain Perl version of doing things if you need to maintain Perl code running on an older version of Perl. It also shows you modern, cleaner and shorter approaches for when you have the freedom to use a recent version of Perl and CPAN modules.
Table of Contents
-
Preface
- Error reporting
- Changes
- v0.06 2018-05-05
- v0.05 2018-04-04
- v0.04 2018-03-24
-
Overview
- Perl tutorial
-
Introduction
- Installing and getting started with Perl
- The Hash-bang line, or how to make a Perl scripts executable on Linux
- Perl Editor
- How to get Help for Perl?
- Perl on the command line
- Core Perl documentation and CPAN module documentation
- POD - Plain Old Documentation
- Debugging Perl scripts
-
Scalars
- Common Warnings and Error messages in Perl
- Prompt, read from STDIN, read from the keyboard in Perl
- Automatic string to number conversion or casting in Perl
- Conditional statements, using if, else, elsif in Perl
- Boolean values in Perl
- Numerical operators
- String operators: concatenation (.), repetition (x)
- undef, the initial value and the defined function of Perl
- Strings in Perl: quoted, interpolated and escaped
- Here documents, or how to create multi-line strings in Perl
- Scalar variables
- Comparing scalars in Perl
- String functions: length, lc, uc, index, substr
- Number Guessing game
- while loop
- Scope of variables in Perl
- Short-circuit in boolean expressions
-
Files
- How to exit from a Perl script?
- Standard output, standard error and command line redirection
- Warning when something goes wrong
- What does die do?
- Writing to files with Perl
- Appending to files
- Open and read from text files
- Don’t Open Files in the old way
- Reading and writing binary files in Perl
- EOF - End of file in Perl
- tell how far have we read a file
- slurp mode - reading a file in one step
-
Lists and Arrays
- Perl for loop explained with examples
- Perl Arrays
- Processing command line arguments - @ARGV in Perl
- How to process command line arguments in Perl using Getopt::Long
- Advanced usage of Getopt::Long for accepting command line arguments
- Perl split - to cut up a string into pieces
- How to read a CSV file using Perl?
- join
- The year of 19100
- Scalar and List context in Perl, the size of an array
- Reading from a file in scalar and list context
- STDIN in scalar and list context
- Sorting arrays in Perl
- Sorting mixed strings
- Unique values in an array in Perl
- Manipulating Perl arrays: shift, unshift, push, pop
- Reverse Polish Calculator in Perl using a stack
- Using a queue in Perl
- Reverse an array, a string or a number
- The ternary operator in Perl
- min, max, sum in Perl using List::Util
- qw - quote word
-
Subroutines
- Subroutines and functions in Perl
- Passing multiple parameters to a function in Perl
- Variable number of parameters in Perl subroutines
- Understanding recursive subroutines - traversing a directory tree
-
Hashes
- Hashes in Perl
- Creating a hash from an array in Perl
- Perl hash in scalar and list context
- exists - check if a key exists in a hash
- How to sort a hash in Perl?
- Count the frequency of words in text using Perl
-
Regular Expressions
- Introduction to Regexes in Perl 5
- Regex character classes
- Regex: special character classes
- Perl 5 Regex Quantifiers
- trim - removing leading and trailing white spaces with Perl
- Perl 5 Regex Cheat sheet
-
Shell related functionality
- What are -e, -z, -s, -M, -A, -C, -r, -w, -x, -o, -f, -d , -l in Perl?
- Current working directory in Perl (cwd, pwd)
- Running external programs from Perl with system
- How to remove, copy or rename a file with Perl
- Reading the content of a directory
- Traversing the filesystem - using a queue
-
CPAN
- Download and install Perl
- Installing a Perl Module from CPAN on Windows, Linux and Mac OSX
- How to change @INC to find Perl modules in non-standard locations
- How to add a relative directory to @INC
-
Examples for using Perl
- How to replace a string in a file with Perl
- How to read an Excel file in Perl
- How to create an Excel file with Perl?
- Sending HTML e-mail using Email::Stuffer
- Perl/CGI script with Apache2
- JSON in Perl
- Simple Database access using Perl DBI and SQL
- Reading from LDAP in Perl using Net::LDAP
-
Common warnings and error messages
- Global symbol requires explicit package name
- Variable declaration in Perl
- Use of uninitialized value
- Barewords in Perl
- Name “main::x” used only once: possible typo at …
- Unknown warnings category
- Can’t use string (…) as an HASH ref while “strict refs” in use at …
- Symbolic references in Perl
- Can’t locate … in @INC
- Scalar found where operator expected
- “my” variable masks earlier declaration in same scope
- Can’t call method … on unblessed reference
- Argument … isn’t numeric in numeric …
- Can’t locate object method “…” via package “1” (perhaps you forgot to load “1”?)
- AUTOLOAD - handling Undefined subroutines
- Useless use of hash element in void context
- Useless use of private variable in void context
- readline() on closed filehandle in Perl
- Possible precedence issue with control flow operator
- Scalar value … better written as …
- substr outside of string at …
- Have exceeded the maximum number of attempts (1000) to open temp file/dir
-
Extra articles
- Multi dimensional arrays in Perl
- Multi dimensional hashes in Perl
- Minimal requirement to build a sane CPAN package
- Statement modifiers: reversed if statements
- What is autovivification?
-
From other books
- Splice to slice and dice arrays in Perl
- How to improve my Perl program?
- Index
Bundles that include this book
About the Author
Gabor Szabo has been programming for more than 30 years in a number of languages and in various environments. He used to do DevOps before there was a name for it.
These days he usually helps companies improve their engineering practices by introducing test automation, CI, CD. Sometimes this includes building internal web sites. Gabor also loves explaining things and provides training to his clients.
Gabor also has a number of websites. Each one using a different technology.
Gabor has been writing Perl since 1995 and teaching it since 2000. He is the author of the Perl Maven site including the Perl Tutorial. He has taught web development with Perl Dancer many time including at Perl Conferences in Europe and USA. Gabor is the chief editor of the Perl Weekly newsletter.
He is also the author and maintainer of Perl 6 Maven site that runs on Bailador.
The Code And Talk and Pydigger sites use Python Flask.
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