Perl钻石操作符输入

Perl中一种有趣输入的方法，钻石操作符<>

例子：

[root@zsd script]# cat ex1_2.pl
#!/usr/bin/perl
while(<>){
        chomp;
        print "It was $_ that I saw!\n";
}
[root@zsd script]# cat fred
hello everyone
i see
sky is great player
[root@zsd script]# ./ex1_2.pl fred
It was hello everyone that I
It was i see that I
It was sky is great player that I
[root@zsd script]#

它会把fred文件中的内容，当做输入流，进行处理，默认会在$_进行读取