@_ has runtime scope. : Special Variables « Language Basics « Perl

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Perl » Language Basics » Special Variables

@_ has runtime scope.


   



#  Each subroutine has its own copy of @_, 



#!/usr/bin/perl

use warnings;

use strict;

first(1,2,3);

sub first {

    print "In first, arguments are @_\n";

    second(4,5,6);

    print "Back in first, arguments are @_\n";

}

sub second {

    print "In second, arguments are @_\n";

}

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5.	The list separator is the empty string
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10.	A program that uses the $" (dollar and quotation) variable.
11.	A program that uses the $(dollar), variable.
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15.	A simple version of the cat command using $_.
16.	ARGV and the Null Filehandle
17.	ARGV in Perl represents the command-line arguments.
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19.	Alternative names for Perl system variables.
20.	Assign elements in @_ to scalar
21.	Assign string array to @ARGV by using qw
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23.	Build the ARGV array with qw function
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25.	Built-in variables: $_
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31.	Error message is stored in $!
32.	Extracts information from the $] variable.
33.	$! is the error number
34.	$! stores the error message
35.	$" is the separator
36.	$# is the default format
37.	$(dollar), is the separator
38.	$MATCH = $&
39.	$SIG{__DIE__}
40.	$SIG{__WARN__} = 'IGNORE';
41.	$SIG{__WARN__} = sub {die "Warning: $_[0]"};
42.	$\ is 'END_OF_OUTPUT'
43.	$^ is the format header
44.	$^O stores the name of the operating system
45.	$^S: is inside eval
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48.	$_ for print function
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52.	File-searching program using $ARGV.
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55.	If $_contains needle, the string is printed.
56.	Integer signal
57.	Lines Remaining on the Page: $-
58.	List all command line argument
59.	Local builtin var
60.	Locate all numbers less than 6
61.	Manipuate @_ and return @_
62.	Mannually change the $1 variable
63.	Match: $&
64.	Perl 5 Built-In Variables
65.	Perl's modules reside in the directories named in the @INC array, or subdirectories
66.	Perl's special arrays
67.	Perl's special variables
68.	Postmatch $'
69.	Prematch: $`
70.	Print all command line argument
71.	Print the default variable's ($_) value
72.	Quick Sum
73.	Read and set environment variables?
74.	Read lines from supplied filenames
75.	Reference element in @_
76.	Resetting array base
77.	Retrieving the Entire Pattern: $&
78.	Saving in the $& special scalar
79.	Set the $/ and chomp
80.	Special Variables
81.	System variables that control how write sends output to a file
82.	Test of open and die with $!.
83.	The $_ Scalar Variable
84.	The @* field
85.	The @ISA Array and Calling Methods
86.	The Argument Vector @ARGV
87.	The Pattern-Matching Operator and $_
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96.	Using $_ (dollar underscore)
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98.	Using $_ variable with while statement
99.	Using %SIG to define our own signal handlers
100.	Using @_ directly
101.	Using __LINE__ to output line number
102.	Using eof and <> together.
103.	Using the $. variable.
104.	Using the $;(dollar and semicolon) variable.
105.	Using the @_ to reference the parameter
106.	Using the Default Variable $_
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115.	You display the name of the current file with the __FILE__ token
116.	foreach (@_)
117.	foreach loop and $_
118.	or die $!
119.	or die $^E;
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122.	print $]; (Perl version number)
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125.	shift: defaults to shifting @ARGV
126.	time - $^T
127.	undef $/;

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