perl 的一些默认变量

饼干lr

Predefined Variables
Perl provides a large number of predefined variables. The following is a list of some common predefined variables:

$_
The default input and pattern-searching space.

$.
Current line number for the last filehandle accessed.

$@
The Perl syntax error message from the last eval() operator.

$!
Yields the current value of the error message, used with die.

$0
Contains the name of the program being executed.

$$
The process number of the Perl running this script.

$PERL_VERSION / $^V
The revision, version, and subversion of the Perl interpreter.

@ARGV
Contains the command-line arguments.

ARGV
A special filehandle that iterates over command-line filenames in @ARGV.

@INC
Search path for libarary files.

@_
Within a subroutine the array @_ contains the parameters passed to that subroutine.

%ENV
The hash %ENV contains your current environment.

%SIG
The hash %SIG contains signal handlers for signals.

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