Perl 利用grep 判断元素是否在数组里

[oracle@june2 ~]$ cat a3.pl 
my @allow_command=qw/ a1 a2 a3 a4/;
my $binary='a4';
if (grep m/$binary/,@allow_command ){print "11111111
"};
[oracle@june2 ~]$ perl a3.pl 
11111111