A.4. Perl Modules

Table A.6. General Programming

Module	Description
Benchmark	Checks and compares the speed of running code in CPU time.
Config	Accesses Perl configuration options from the %Config hash.
Env	Converts the %ENV hash to scalars containing environment variables; e.g., $ENV{HOME} becomes $HOME.
English	Provides scalars in English or awk names for special variables; e.g., $0 can be represented as $PROGRAM_NAME.
Getopt	Provides for processing of command-line options and switches with arguments.
Shell	Used to run shell commands within Perl scripts by treating the commands as subroutines; e.g., $today=date();
Symbol	Generates anonymous globs with gensym() and qualifies variable names with qualify().

Table A.7. CGI

Module	Description
CGI	CGI (Common Gateway Interface) class.
CGI::Apache	Used with CGI.pm and the Perl-Apache API.
CGI::Carp	Handles HTTP error messages and creates error log files.
CGI::Cookie	Interfaces with Netscape cookies.
CGI::Fast	Interfaces with Fast CGI.
CGI::Pretty	Produces pretty formatted HTML code.
CGI::Push	Simple interface to server push.

Table A.8. Error Handling

Module	Description
Carp	Generates die-like error messages to report line numbers of the calling routine where the error occurred. The subroutines that can be called from this module are carp(), croak(), and confess().
Errno	Loads the libc errno.h defines.
Sys::Syslog	Provides a Perl interface to the UNIX syslog(3) library calls.

Table A.9. File Handling

Module	Description
Cwd	Gets the pathname of the current working directory. Produces an error message if used with the -w switch.
DirHandle	Provides an object-oriented interface for directory handles.
Fcntl	Loads the libc fcntl.h (file control) defines.
File::Basename	Splits a filename into components or extracts a filename or a directory from full directory path.
File::CheckTree	Runs file tests on a collection of files in a directory tree.
File::Copy	Used to copy files or filehandles.
File::DosGlob	Does DOS-like globbing.
File::Find	Used to traverse a UNIX file tree.
File::Finddepth	Searches depth-first through a file system.
File::Glob	Does UNIX filename globbing.
File::Path	Creates and removes a list of directories.
File::Spec	Performs portable operations on filenames.
FileCache	Allows more files to be opened than permitted by the system.
FileHandle	Provides an object-oriented interface to filehandle access methods.
SelectServer	Saves and restores a selected filehandle.
flush.pl	Writes any data remaining in the filehandle's buffer or prints an expression and then flushes the buffer.
pwd.pl	Sets the PWD environment variable to the present working directory after using chdir.
stat.pl	Puts the values returned by the stat function into scalars—$st_dev, $st_ino, $st_mode, $st_nlink, $st_uid, $st_rdev, $st_atime, $st_mtime, $st_ctime, $st_blksize, $st_blocks.

Table A.10. Text Processing

Module	Description
Pod::Text	Converts pod documentation to ASCII-formatted text.
Search::Dict	Searches for a string in a dictionary (alphabetically ordered) file and sets the file pointer to the next line.
Term::Complete	Provides a filename-completion-like interface for prompting a user for partial input that can be completed by pressing a Tab key or a complete list of choices by pressing <Ctrl>-d.
Text::Abbrev	Creates an abbreviation table, a hash consisting of key/value pairs from a list. The key is the abbreviation and the value is the string that was abbbreviated; e.g., ma/mail, mo/more.
Text::ParseWords	Parses a line of text into a list of words like the shell does, stripping leading whitespace.
Text::Soundex	Maps words to four character-length codes that roughly correspond to how the word is pronounced or sounds.
Text::Tabs	Expands tabs into spaces and unexpands tabs to spaces.
Text::Warp	Wraps text into a paragraph.

Table A.11. Database Interfaces

Module	Description
AnyDBM_File	A UNIX-based module providing framework for multiple DBMs.
DB_File	Provides access to Berkeley DB manager. See ftp//ftp.cs.berkeley.edu/ucb/4bsd.
DBI	Returns a list of DBs and drivers on the system, and functions to interact with the database.
GDBM_File	Provides access to the GNU database manager. See ftp://prep.ai.mit.edu/pub/gnu.
NDBM_File	A UNIX-based module providing an interface to NDBM files.
ODBM_File	A UNIX-based module providing an interface to ODBM files.
SDBM_File	A UNIX-based module providing an interface to SDBM files.

Table A.12. Math

Module	Description
bigrat.pl	Enables infinite precision arithmetic on fractions.
Math::BigFloat	Supports arbitary-sized floating point arithmetic.
Math::BigInt	Supports arbitrary-sized integer arithmetic.
Math::Complex	Supports complex numbers to demonstrate overloading.
Math::Trig	Supports trigonometric functions.

Table A.13. Networking

Module	Description
chat2.pl	Allows Perl to manipulate interactive network services such as FTP.
comm.pl	Newer than chat2.pl. Allows Perl to manipulate interactive services.
IPC::Open2	Opens a process for reading and writing to allow data to be piped to and from an external program.
IPC::Open3	Opens a process for reading, writing, and error handling so that data can be piped to and from an external program.
Net::Ping	Checks whether a remote machine is up.
Socket	Creates sockets and imports socket methods for interprocess communication and loads socket.h header file.
Sys::Hostname	Gets the hostname for the system.

Table A.14. Time and Locale

Module	Description
I18N::Collate	Compares 8-bit scalar data according to the current locale.
Time::gmtime	An interface to Perl's built-in gmtime() function.
Time::Local	Computes the UNIX time (the number of non-leap-year seconds since January 1, 1970) from local and GMT (UTC) time.
Time::localtime	An interface to Perl's built-in localtime() function.

Table A.15. Terminals

Module	Description
Term::Cap	Provides low-level functions to manipulate terminal configurations as a terminal interface to the termcap database.

Table A.16. Object-Oriented Module Functions

Module	Description
Autoloader	For large modules, loads in only needed sections of a module.
AutoSplit	Splits module into bite-sized chunks for autoloading.
Devel::SelfStubber	Generates stubs for self-loading modules to ensure that if a method is called, it will get loaded.
DynaLoader	Used to automatically and dynamically load modules.
Exporter	Used by other modules to make methods and variables available through importation.
overload	Used to overload mathmatical operations.
Tie::Hash	Provides methods for tying a hash to a package.
Tie::Scalar	Provides methods for tying a scalar to a package.
Tie::SubstrHash	Provides a hash-table-like interface to an array with constant key and record size.

Table A.17. Language Extension

Module	Description
ExtUtils::Install	For installing and deinstalling platform-dependent Perl extensions.
ExtUtils::Liblist	Determines what libraries to use and how to use them.
ExtUtils::MakeMaker	Creates a Makefile for a Perl extension in the extension's library.
ExtUtils::Manifest	Automates the maintenance of MANIFEST files, consisting of a list of filenames.
ExtUtils::Miniperl	Writes C code for perlmain.c, which contains the bootstrap code for making archive libraries needed by modules available from within Perl.
ExtUtils::Mkbootstrap	Is called from the extension's Makefile to create a bootstrap file needed to do dynamic loading on some systems.
ExtUtils::Mksysmlists	Writes linker option files used by some linkers during the creation of shared libraries for dynamic extensions.
ExtUtils::MM_OS2	Overrides the implementation of methods, causing UNIX behavior.
ExtUtils::MM_Unix	To be used with MakeMaker to provide methods for both UNIX and non-UNIX systems.
ExtUtils::MM_VMS	Overrides the implementation of methods, causing UNIX behavior.
Fcntl	Translates the C fcntl header file.
POSIX	Provides the Perl interface to IEEE std 1003.1 identifiers.
Safe	Provides private compartments where unsafe Perl code can be evaluated.
Test::Harness	Used by MakeMaker to run test scripts for Perl extensions and produce diagnostics.