my $datadir="/user1/localfiles/data/"
opendir LOCALDIR, "$datadir" or die "unable to open $datadir\a\n";
my @localfiles=grep/(^file-15a_62_200405)&&(.txt$)/i readdir LOCALDIR;
foreach my $file(@localfiles)
{
print "$file\n";
}

##</code><code>##

my @localfiles=grep/.txt$/i readdir LOCALDIR;

##</code><code>##

my @localfiles=grep/^file-15a_62_200405/i readdir LOCALDIR;