| %ENV | The hash %ENV contains your current environmental values. Setting a value in ENV (like $ENV{home}='/usr/bin/perl';) changes the environment for any child processes you subsequently fork() off. |
| %INC | The hash %INC contains entries for each filename included via the do, require, or use operators. just print %inc in your perl program and you will find it! |
| @INC | The array @INC contains the list of places that the do EXPR , require, or use constructs look for their library files. It initially consists of the arguments to any -I command-line switches, followed by the default Perl library. |
| @ARGV | This variable is an array of the arguments passed to the script. |
| %SIG | This variable is an associative array that links the standard signals to values. These values dictate the way that the script processes those signals. You can assign signal-handling subroutines to certain signals or set the script to ignore certain signals. |
| $a $b | |
| $? | If a Perl script spawns child processes, you can examine their error codes by using this variable.
|
| $@ | The Perl syntax error message from the last eval() operator. |
| $$ | The process id (number) of the Perl running this script. |
