Learn how to open and close a file in Perl 5.
- [Voiceover] Continuing with our quick start,…we're going to examine a simple script…that counts the lines in a file.…Here, I have opened a working copy of countlines.pl…from Chapter 2 of the Exercise Files.…This also uses the file linesfile.txt,…so if I just double click on this here in Komodo Edit,…you'll notice that that's what the file looks like.…It's got 50 lines of text, and they're numbered,…and they just say, "This is a line of text."…So I'll go ahead and close that,…and what this script does, is it opens that file,…and it counts the lines of text,…and it tells you how many there are.…
So this is a rudimentary script,…counts the lines in a small file.…It demonstrates opening, reading, and closing a file.…It reads the entire file into memory,…so it'll only work on reasonably small files,…and let's just take a look at how it works.…So on line 8, we declare a variable,…and that's right here.…The my keyword declares the variable to be lexically scoped…in the enclosing block or file,…so that makes it a local variable to this file.…
Watch to learn the details of the Perl syntax, from variables, conditionals, loops, and data structures to regular expressions, functions, and references. A quick-start guide is included for experienced developers who want to get up and running with Perl 5 fast, and the entire course is recommended for both new and experienced programmers alike. Later chapters cover file handling and reusing code with Perl modules, plus Perl best coding practices.
- Understanding Perl's general syntax and the anatomy of a Perl script
- Writing statements and expressions
- Creating assignments
- Working with variables and strings
- Using data types effectively
- Defining logical flow with conditionals and loops
- Using special variables
- Using Perl operators
- Performing simple Perl programming tasks with expressions
- Matching data
- Defining and calling functions
- Using references
- Handling files in the file I/O
- Using built-in functions
- Reusing code with modules
- Coding with Perl best practices
Skill Level Intermediate
1. Setting Up
About Perl3m 36s
2. Quick Start
3. Basic Syntax
4. Values and Variables
7. Special Variables
9. Regular Expressions
11. References and Structures
12. File I/O
13. Built-In Functions
15. Best Practices
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