General Programming

Benchmark Checks and compares the spead of running code in CPU time.
Config Accesses Perl configuration option from the %Config hash.
Env Converts the %ENV hash to scalar 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().

CGI

CGI CGI (Common Gateway Interface) class.
CGI::Apache Used with CGI.pm and the Perl-Apathe API.
CGI::Carp Handles HTTP error messages and creates error log file.
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.

Error Handling

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.

File Handling

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 directorues.
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 buffer.
pwd.pl Sets the PWD environment variable to the present working directory after chdir.
stat.pl Puts the values returned by the stat function into scalars - $st_dev, $st_into, $st_mode, $st_nlink, $st_uid, $st_rdev, $st_atime, $st_mtime, $st_ctime, $st_blksize, $st_blocks.

Text Proccessing

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 abbreviated, 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 ot sounds.
Text::Tabs Expands tabs into spaces and unexpands tabs to spaces.
Text::Warp Wraps text into a paragraph.