Perl 子程序变量外部使用--又称为闭包

my  $var = "aaaaaaaaa";
print "1---$var is $var
";
&fun1;
&fun2;

#子程序用的变量会被销毁

print "3---$var2 is $var2
";

print "4----$var2 is $$var3
";

sub fun1{
	print "2----$var is $var
"};

##外部变量在子程序中仍旧有用



sub fun2{
	my $var2="bbbbbbbbbb";
	# my  $var3=$var2;
	   $var3=$var2;
	 print "$var3 is $$var3
";
 };
 

#此时的结果:
G:运维系统开发Tk1>perl 4.pl
1---$var is aaaaaaaaa
2----$var is aaaaaaaaa
$var3 is bbbbbbbbbb
3---$var2 is
4----$var2 is

要想子程序里的变量在外部生效, 引用变量必须为全局变量

G:运维系统开发Tk1>perl 4.pl
1---$var is aaaaaaaaa
2----$var is aaaaaaaaa
$var3 is bbbbbbbbbb
3---$var2 is
4----$var2 is bbbbbbbbbb