Network Programming with Perl

 
Network Programming with Perl

By Lincoln  D.  Stein

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Table of Contents
Appendix B.   Perl Error Codes and Special Variables
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Other Perl Globals

Table B.3 lists other Perl globals used in the body of this book. The first column is the Perl punctuation variable, and the second is its English-language equivalent when the English module is loaded.

Table B.3. Other Perl Globals

Variable English Description
$? $CHILD_ERROR Status returned by the last pipe close, backtick, or successful call to wait() ; a status of 0 generally indicates that the child terminated without error
$! $ERRNO Error message from the last failed system call
$^E $EXTENDED_OS_ERROR Extended error information from non-UNIX operating systems
$<digit>   Last matched subexpression from a successful pattern match (e.g., $1 , $2 )
$& $MATCH Entire string matched by the last successful pattern match
$` $PREMATCH String preceding whatever matched the last successful pattern match
$' $POSTMATCH String following whatever matched the last successful pattern match
$$ $PID Process ID of the current process
$< $UID Real user ID (UID) of the current process
$> $EUID Effective UID of the current process; corresponds to the effective privileges that a set- userid script runs under
$( $GID Real group ID (GID) of the current process
$) $EGID Effective GID of the current process; corresponds to the effective privileges that a set-groupid script runs under
$0 $PROGRAM_NAME Name of the script being run
$ARGV   Name of the current file when reading from <>
@ARGV   Array of command-line arguments
@INC   List of packages that the current script or module inherits from when using Perl's object-oriented features
@_   Within a subroutine, the array containing the arguments passed to the subroutine
%ENV   A hash containing the current environment variables
%SIG   A hash containing the names of signals to be caught and the handlers to invoke when they arrive
   
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