Perl for System Administration

Preparing to Learn Perl

• Things you need to know and do in order to run Perl and learn Perl programming
• A module designed for complete beginners
• The Perl compiler/interpreter
• Perl under Unix/Linux
• Perl under MS Windows 2000/NT/95/98/ME (perl.exe)
• ActiveState Perl
• Making programs executable
• Perl from the command line
• Specify the perl compiler/interpreter (#!)
• Using plain text
• Writing a very simple program
• Running a very simple program
• Basic syntax

Perl: The Absolute Minimum

• Enough of the language to get started
• The print command
• Variables
• Scalars - numbers and 'strings'
• Assignment
• Simple conditional tests - if "strings" "\n"
• Lists
• Arrays - for storing lists
• foreach
• Hashes
• Other loops: while, for, do, until
• Arrays - the rest
• Simple input, e.g. while(<>)
• Functions overview - recognising, writing, using
• Regular expressions - perlre
• Simple file handling - open, print
• Subroutines - parameters in and out, listification, local variables
• Help - perldoc, books, web

Perl: Beyond the Basics

• More flow control
• Statement modifiers
• Quoting mechanisms - qq(), etc
• Here documents
• Uppercase/lowercase conversion
• Splitting strings into lists
• Joining lists into strings
• Filtering lists with map
• Sorting lists
• The importance of context
• Assignment shortcuts
• Scoping rules
• Special variables

Complex Data Structures & References

• Limits of flat lists
• Nesting arrays
• Array references
• Anonymous arrays
• Named array references
• Passing multiple arrays to/from functions
• Hashes of arrays
• Hash references
• Arrays of hashes
• Hashes of hashes
• Complex nested data structures
• Code references
• Dispatch tables

Finding Out More For Yourself

• How to read Perl's documentation
• Where to find more information
• Knowing what's out there to look for
• FAQs

The Perl Debugger & Debugging Perl

• Avoiding bugs
• Perl's built-in debugger
• Invoking the debugger
• What you can do with the debugger
• Understanding the debugger's command line interface
• Knowing the debugger's basic command set
• Exploring some extended functions
• Graphical debuggers
• Alternative debugging techniques

Using Perl Modules from CPAN

• The Comprehensive Perl Archive Network (CPAN)
• Why effective Perl programmers are efficient CPAN users
• CPAN's philosophy
• Finding modules
• Installing Modules
• Using modules
• Some particularly useful modules

Command-Line Perl

• General principles
• Using Perl as a filter
• Awk-like Perl
• Many real world examples
• Many examples using regular expressions
• Command line flags

A Whistle-Stop Tour of the World of Perl

• Wheels you don't need to re-invent
• Common recipes
• Common pitfalls

Advanced File Processing with Perl

• Types of open
• Filehandles
• Reading line by line
• Reading paragraph by paragraph
• Reading entire files
• Special variables
• The flip-flop operator (..)
• File test functions
• Pipes

Perl Security Issues

• Potential security pitfalls
• Coding for security
• Taint checking
• Dangerous environment variables
• File input
• Set-user-id Perl programs
• Permissions and users

System interaction

• Connecting to other programs
• Unsafe pipes
• Using IO::Pipe
• Grabbing a program's output
• Other ways to run programs

Managing Users and Processes with Perl

• User identity across platforms
• Process control
• Scheduling events
• Managing disk quotas
• Querying filesystem usage
• Monitoring file operations
• Monitoring network operations
• Related perl modules

Managing Networks with Perl

• Host Files
• NIS and NIS+
• DNS
• WHOIS
• LDAP
• ADSI
• Sending and receiving email
• Related modules

Logging with Perl

• Text logs
• Binary logs
• Handling state
• Disk usage problems
• Log analysis
• Log munging
• Logging related modules