If the "solution" is

print if /\Q$pattern\E/;
[download]

then $pattern doesn't contains a regexp pattern as its name implies. The variable should be renamed

my $search_str = $1;
...
print if /\Q$search_str/;
[download]

or quotemeta should be called earlier.

my $pattern = quotemeta($1);  # aka "\Q$1"
...
print if /$pattern/;
[download]