Perl tutorial

Introduction

1. Install Perl, print Hello World, Safety net (use strict, use warnings)
2. #!/usr/bin/perl - the hash-bang line
3. Editors, IDEs, development environment for Perl
4. Getting Help
5. Perl on the command line
6. Core Perl documentation, CPAN module documentation
7. POD - Plain Old Documentation
8. Debugging Perl scripts

Scalars

1. Common warnings and error messages
2. Prompt, read from STDIN, read from the keyboard
3. Automatic string to number conversion
4. Conditional statements: if
5. Boolean (true and false) values in Perl
6. Numerical operators
7. String operators
8. undef, the initial value and the defined function
9. Strings in Perl: quoted, interpolated and escaped
10. Here documents
11. Scalar variables
12. Comparing scalars
13. String functions: length, lc, uc, index, substr
14. Number Guessing game (rand, int)
15. Perl while loop
16. Scope of variables in Perl
17. Boolean Short circuit

Files

1. exit
2. Standard Output, Standard Error and command line redirection
3. warn
4. die
5. Writing to files
6. Appending to files
7. Open and read from files using Perl
8. Don't open files in the old way
9. Binary mode - reading and writing binary files
10. eof, end of file in Perl
11. tell
12. seek
13. truncate
14. Slurp mode

Lists and Arrays

1. Perl foreach loop
2. The for loop in Perl
3. Lists in Perl
4. Using Modules
5. Arrays in Perl
6. Process command line parameters @ARGV
7. Process command line parameters using Getopt::Long
8. Advanced usage of Getopt::Long for accepting command line arguments
9. split
10. How to read and process a CSV file? (split, Text::CSV_XS)
11. join
12. The year of 19100 (time, localtime, gmtime) and introducing context
13. Context sensitivity in Perl
14. Reading from a file in scalar and list context
15. STDIN in scalar and list context
16. Sorting arrays in Perl
17. Sorting mixed strings
18. Unique values in an array in Perl
19. Manipulating Perl arrays: shift, unshift, push, pop
20. Stack
21. Queue
22. reverse
23. The ternary operator
24. Loop controls: next and last
25. min, max, sum using List::Util
26. qw - quote word

Subroutines

1. Subroutines and Functions in Perl
2. Passing multiple parameters to a function
3. Variable number of parameters
4. Returning a list, returning an array
5. Recursive subroutines

Hashes

1. Perl Hashes (dictionary, associative array, look-up table)
2. Creating hash from an array
3. Perl hash in scalar and list context
4. exists hash element
5. delete hash elements
6. Sorting a hash
7. Count word frequency in a text file

Regular Expressions

1. Introduction to Regular Expressions in Perl
2. Regex: character classes
3. Regex: special character classes
4. Regex: quantifiers
5. Regex: Greedy and non-greedy match
6. Regex: Grouping and capturing
7. Regex: Anchors
8. Regex options and modifiers
9. Substitutions (search and replace)
10. trim - remove leading and trailing spaces
11. Perl 5 Regex Cheat sheet

Shell related functionality

1. Perl -X operators
2. Perl pipes
3. Unix commands: chmod, chown, cd, mkdir, rmdir, ln, ls
4. Unix commands: pwd - current working directory
5. Running external programs using system
6. Capturning the output of an external program using qx or backticks
7. Capturing output asynchronously
8. Capturing both STDOUT and STDERR
9. Unix commands: rm, mv, cp: How to remove, copy or rename a file with Perl
10. Windows/DOS commands: del, ren, dir
11. File globbing (Wildcards)
12. Directory handles
13. Traversing directory tree manually with recursion
14. Traversing directory tree manually using a queue and using find.

CPAN

1. Download and install Perl (Strawberry Perl or manual compilation)
2. Download and install Perl using Perlbrew
3. Locating and evaluating CPAN modules
4. Downloading and installing Perl Modules from CPAN
5. How to change @INC to find Perl modules in non-standard locations?
6. How to change @INC to a relative directory
7. local::lib

Examples for using Perl

1. How to replace a string in a file with Perl? (slurp)
2. Reading Excel files using Perl
3. Creating Excel files using Perl
4. Sending e-mail using Perl
5. CGI scripts with Perl
6. Parsing XML files
7. Reading and writing JSON files
8. Database access using Perl (DBI, DBD::SQLite, MySQL, PostgreSQL, ODBC)
9. Accessing LDAP using Perl

Common warnings and error messages

1. Global symbol requires explicit package name ...
2. .. also explained in Variable declaration in Perl
3. Use of uninitialized value
4. Bareword not allowed while "strict subs" in use
5. Name "main::x" used only once: possible typo at ...
6. Unknown warnings category
7. Can't use string (...) as a HASH ref while "strict refs" in use at ... ...
8. ... explained in Symbolic references in Perl
9. Can't locate ... in @INC
10. Scalar found where operator expected
11. "my" variable masks earlier declaration in same scope
12. Can't call method ... on unblessed reference
13. Argument ... isn't numeric in numeric ...
14. Can't locate object method "..." via package "1" (perhaps you forgot to load "1"?)
15. Odd number of elements in hash assignment
16. Possible attempt to separate words with commas
17. Undefined subroutine ... called
18. Useless use of hash element in void context
19. Useless use of private variable in void context
20. readline() on closed filehandle
21. Possible precedence issue with control flow operator
22. Scalar value better written as ...
23. substr outside of string at ...
24. Have exceeded the maximum number of attempts (1000) to open temp file/dir
25. Deep recursion on subroutine
26. Use of implicit split to @_ is deprecated ...

Extra articles

1. Multi dimensional arrays
2. Multi dimensional hashes
3. Minimal requirement to build a sane CPAN package
4. Statement modifiers: reversed if statements
5. autovivification
6. Formatted printing in Perl using printf and sprintf

From other books

1. Splice to slice and dice arrays in Perl
2. How to improve your Perl code