Perl for system administration — a 4-day course

Preparing to learn perl

• Things you need to know and do in order to run Perl programs 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 (chmod +x)
• Perl from the command line (perl command)
• Specify the perl compiler/interpreter (#!)
• Using plain text for programs
• 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 function
• Variables
• Scalars — numbers and strings
• Assignment
• Simple conditional tests — if
• Lists
• Arrays — for storing lists
• foreach loops
• Hashes
• Other loops: while, for, do, until
• Arrays — the rest
• Simple input, e.g., while(<>)
• Functions overview — recognising, writing, using
• Simple file handling — open, print
• Subroutines — parameters in and out, listification, local variables (my)
• Help — perldoc, books, web

Regular expressions

• Text manipulation with regular expressions
• Matching strings
• Matching the default variable
• Case-sensitivity and matching
• Special characters
• Special characters: where
• Special characters: what
• Special characters: how many
• Built-in character classes
• Built-in character class examples
• Capturing
• Regular expression examples
• Substitution
• Global substitutions

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

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

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

Command-Line Perl

• General principles
• Using Perl as a filter
• Editing files in-place
• Many real world examples
• Command line flags
• Many examples using regular expressions

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
• DNS
• NIS lookups
• WHOIS
• LDAP
• ADSI
• Sending and receiving email
• Related modules

Logging with Perl

• Text logs
• Logs used on Unix
• Handling state
• Disk usage problems
• Log analysis
• Log munging
• Logging related modules