数字 ==
字符窜 eq
逻辑操作符:
[oracle@jhoa big]$ cat a2.pl
if ( 2 > 1 && 3 > 2){print "ok
"};
[oracle@jhoa big]$ perl a2.pl
ok
&& 条件同时成立, 具有短路功能, 当左边不满足条件时,就不看右边了。
[oracle@jhoa big]$ cat a2.pl
if ( 1 > 2 && 3 > 2){print "ok
"};
[oracle@jhoa big]$ perl a2.pl
[oracle@jhoa big]$
[oracle@jhoa big]$ cat a2.pl
if ( 2 > 1 && 1 > 2){print "ok
"};
[oracle@jhoa big]$ perl a2.pl
[oracle@jhoa big]$
$. 包含你的输入文件的当前行号:
Perl 引用:
[oracle@jhoa big]$ cat a3.pl
$var = "aaaaaa";
$ref_to_var = $var;
print "1--$var is $var
";
print "2--$ref_to_var is $ref_to_var
";
print "3--$ref_to_var is $$ref_to_var
";
[oracle@jhoa big]$ perl a3.pl
1--$var is aaaaaa
2--$ref_to_var is SCALAR(0x15310080)
3--$ref_to_var is aaaaaa