Using the $. variable. : Special Variables « Language Basics « Perl

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Perl » Language Basics » Special Variables

Using the $. variable.


   

#!/usr/local/bin/perl 



open (FILE1, "file1") || 

die ("Can't open file1\n"); 

open (FILE2, "file2") || 

die ("Can't open file2\n"); 

$input = <FILE1>; 

$input = <FILE1>; 

print ("line number is $.\n"); 

$input = <FILE2>; 

print ("line number is $.\n"); 

$input = <FILE1>; 

print ("line number is $.\n");

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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.
18.	Aliases and Values
19.	Alternative names for Perl system variables.
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28.	Capturing fatal errors
29.	Catching the sigINT signal
30.	Code the $_ specifically
31.	Compare value entered with number with underscore
32.	Error message is stored in $!
33.	Extracts information from the $] variable.
34.	$! is the error number
35.	$! stores the error message
36.	$" is the separator
37.	$# is the default format
38.	$(dollar), is the separator
39.	$MATCH = $&
40.	$SIG{__DIE__}
41.	$SIG{__WARN__} = 'IGNORE';
42.	$SIG{__WARN__} = sub {die "Warning: $_[0]"};
43.	$\ is 'END_OF_OUTPUT'
44.	$^ is the format header
45.	$^O stores the name of the operating system
46.	$^S: is inside eval
47.	$^W: Check the '-w switch'
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51.	$~ is the format
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55.	Get local time from $^T
56.	If $_contains needle, the string is printed.
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59.	List all command line argument
60.	Local builtin var
61.	Locate all numbers less than 6
62.	Manipuate @_ and return @_
63.	Mannually change the $1 variable
64.	Match: $&
65.	Perl 5 Built-In Variables
66.	Perl's modules reside in the directories named in the @INC array, or subdirectories
67.	Perl's special arrays
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77.	Resetting array base
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79.	Saving in the $& special scalar
80.	Set the $/ and chomp
81.	Special Variables
82.	System variables that control how write sends output to a file
83.	Test of open and die with $!.
84.	The $_ Scalar Variable
85.	The @* field
86.	The @ISA Array and Calling Methods
87.	The Argument Vector @ARGV
88.	The Pattern-Matching Operator and $_
89.	The Substitution Operator and $_
90.	The code executes a line of code you type as long as that line doesn't start with a #
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94.	To list all .pm files by using the @INC array
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96.	Using $, to set the separator for print command
97.	Using $_ (dollar underscore)
98.	Using $_ as the array index
99.	Using $_ variable with while statement
100.	Using %SIG to define our own signal handlers
101.	Using @_ directly
102.	Using __LINE__ to output line number
103.	Using eof and <> together.
104.	Using the $;(dollar and semicolon) variable.
105.	Using the @_ to reference the parameter
106.	Using the Default Variable $_
107.	Using the diamond operator with @ARGV
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114.	You display the name of the current Perl package with __PACKAGE__.
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;
120.	print "Hello, $ENV{USER}!\n";
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122.	print $]; (Perl version number)
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127.	undef $/;

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