Commonly Used Debugging Commands
This section describes how to run the Perl built-in debugger with the 'perl -d' option. Commonly used debugging commands are also provided.
The default Perl engine on Linux systems offers a built-in debugging tool. It is an interact command line driven and
source line level debugger. To invoke the debugger, you need to run Perl with the
debug option: -d. For example, "perl -d MyProgram.pl".
The ActivePerl engine for Windows systems also offers the same built-in debugging tool.
When a Perl program is executed with the debug option, execution will be
stopped at the first executable statement and a debug command prompt will
be displayed ready to take your debug commands.
Commonly used debugging commands:
- h - Printing help information.
- l - Listing next 10 lines of source file.
- n - Executing the program until the next statement in the same code unit.
This is called step-over in many other debugging environments.
- s - Executing a single statement until the next statement in the same code unit
or a subroutine unit called by the current statement.
This is called step-into in many other debugging environments.
p exp - Printing the value of the expression: exp, in a scalar context.
x exp - Printing the value of the expression: exp, in a list context,
and in a nicely formatted way.
b - Setting a breakpoint at the current statement.
b line - Setting a breakpoint at the statement of the specified line.
d - Deleting the breakpoint at the current statement.
d line - Deleting the breakpoint at the statement of the specified line.
c - Continuing the execution until the next statement with a breakpoint.
q - Quitting the debugger environment.
Table of Contents
About This Book
Perl on Linux Systems
ActivePerl on Windows Systems
Data Types: Values and Variables
Expressions, Operations and Simple Statements
User Defined Subroutines
►Perl Built-in Debugger
►Commonly Used Debugging Commands
Debugging Tutorial Session
Name Spaces and Perl Module Files
Symbolic (or Soft) References
Hard References - Addresses of Memory Objects
Objects (or References) and Classes (or Packages)
Typeglob and Importing Identifiers from Other Packages
String Built-in Functions and Performance
File Handles and Data Input/Output
Open Files in Binary Mode
Open Directories and Read File Names
File System Functions and Operations
Image and Picture Processing
Using DBM Database Files
Using MySQL Database Server
Socket Communication Over the Internet
XML::Simple Module - XML Parser and Generator
XML Communication Model
SOAP::Lite - SOAP Server-Client Communication Module
Perl Programs as IIS Server CGI Scripts
CGI (Common Gateway Interface)
XML-RPC - Remote Procedure Call with XML and HTTP
RPC::XML - Perl Implementation of XML-RPC
Integrating Perl with Apache Web Server
CGI.pm Module for Building Web Pages
LWP::UserAgent and Web Site Testing
Converting Perl Script to Executable Binary
Managing Perl Engine and Modules on macOS
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