perl | 匹配多个

zjzc01:/root/test# cat a2.pl 
$a="1 a 2 3 ";

if ($a =~/(a|b)/){print "1111111
"};
zjzc01:/root/test# perl a2.pl 
1111111

zjzc01:/root/test# cat a2.pl 
$a="1 b 2 3 ";

if ($a =~/(a|b)/){print "1111111
"};
zjzc01:/root/test# perl a2.pl 
1111111

zjzc01:/root/test# cat a2.pl 
$a="1 c 2 3 ";

if ($a =~/(a|b)/){print "1111111
"};
zjzc01:/root/test# perl a2.pl 
zjzc01:/root/test#