Either of these work in a directory where I have some *.pm files and a bunch of others:

use strict;

my $pattern = '\.pm$';

opendir(TARGET, ".") or die "Can't open current directory: $!";

# First try
my @targets = grep(/$pattern/, readdir TARGET);
print join("\n", @targets), "\n\n";

# Second try
rewinddir(TARGET);
@targets = grep {/$pattern/} readdir TARGET;
print join("\n", @targets), "\n\n";
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