IO 双引号 输出 输入

#! /usr/bin/perl
use strict;
use warnings;

print "\n---------<STDIN>_store_into_an_array_and_then_chomp()----------\n";
my @lines = <STDIN>;
chomp(@lines);
print "\n---------Input_complete----------\n";
print "@lines";
print "\n---------<STDIN>_store_into_an_array_and_then_chomp()----------\n";

print "\n----------while_\$line__defined_check_EOF---------\n";
my $line;
while (defined($line = <STDIN>)){
    print "I saw $line.\n";
}
print "\n----------while_\$line__defined_check_EOF---------\n";

print "\n--------while_(<STDIN>)-----------\n";
while(<STDIN>){
    print "I saw $_";
}
print "\n--------while_(<STDIN>)-----------\n";

print "\n-------------------------------while(define(\$_ = <STDIN>))-----------------------------\n";
while(defined($_ = <STDIN>)){
    print "I saw $_";
}
print "\n-------------------------------while(define(\$_ = <STDIN>))-----------------------------\n";

print "\n-------------------------------foreach(<STDIN>)-----------------------------\n";
foreach(<STDIN>){
    print "Input line is: $_.";
}
print "\n-------------------------------foreach(<STDIN>)-----------------------------\n";

print "\n------------------------------------------------------------\n";
print "\n------------------------------------------------------------\n";
print "\n------------------------------------------------------------\n";
print "\n------------------------------------------------------------\n";