my $accountsearch = <STDIN>;
chomp $accountsearch;

my $dir = '/path/to/records';
opendir (DIR, $dir);
my @records = readdir(DIR);
closedir (DIR);

if (/.*$accountsearch.*\.txt/ ~~ @records) {
  print $&, "Was found\n";
} else {
  print "No record found for that account number\n";
}