一、数组应用

#!/usr/bin env perl
@zeng = `top -b -n 1`;
foreach (@zeng) {
print "$_n";
}

二、say的用法：自动换行

#!/user/bin env perl
use 5.010; #表示使用perl 5.10的版本。
say "Hello World!";
my @fred = above_average(1..10);
print "@fred is @fredn";
print "(Should be 6 7 8 9 10)n";
my @barney = above_average(100, 1..10);
print "@barney is @barneyn";
print "(Should be just 100)n";
sub average {
  if (@_ == 0) { return }
  my $count = @_;
  my $sum = total(@_);
  $sum/$count;
  }

  sub above_average {
    my $average = average(@_);
    my @list;
    foreach my $element (@_); {
     if ($element > $average) {
        push @list, $element;
    }
  }
  @list;
  }

#!/usr/bin/perl -w
use 5.010;
greet( 'Fred');
greet( 'barney');
sub greet {
  state $last_person;
  my $name = shift;
  print "Hi $name!";
  if ( defined $last_person ) {
    print "$last_person is also here!n";
    }
    else {
        print "You are the first one here!n";
        }
        $last_person = $name;
        }
greet( 'Fred' );
greet( 'barney' );
greet( 'wilma' );
greet( 'Betty' );
sub greet {
    state @names;
    my $name = shift;
    print "Hi $name!";
    if ( @names ) {
        print "I've seen: @namesn";
        }
    else {
        print "You are the first one here!n";
        }
        push @names, $name;
        }

学习perl的unless控制结构
例如：unless($fred=~/^([A-Z_]w*$/i){print"Thevalueof$freddoesn'tlooklikeaPerlidentifiername.n";}使用unless意味着，要么条件为真，要么执行某块代码。这就好像使用if控制

有关perl正则表达式的一些杂项
$也能匹配n见Perl语言入门，page132,注释61/^.*$/能匹配"n"么？能！因为$不仅能匹配行尾，也能匹配n2/^.*$/能匹配"bn"么？能！.能b匹配.n匹配$3/^.*$/能匹配"

perl中heredoc使用说明
格式printEOFyoutextgohereEOFsubusage{printEOF;Usage:test.pl-cconfig,-ffile-llines-cconfigfile-ffilename-lnumberoflinesEOF}NOTE:thelastEOFmuststartatthebeginningoftheline!!!youcanuseotherwordsinstead