#!c:\perl\bin\perl
use Storable; #use this for calling the hash storing functions.

my %dict;  # the hash

while (my $line = <DATA>) {
    chomp $line;
    $dict{$line}++;  # instead of ++ you could also assign some value.
+..
}
store(\%dict, "hash.txt"); #store the hash in the file.

%dict = %{retrieve("hash.txt")}; #retrieve the hash from the file "hash.txt". thus, it only needs to be generated once.
my @inputs = qw(
foo
fooed
fooen
prefoo
postfoo
);

for my $input (@inputs) {
    print "found '$input' in lexicon\n" if exists $dict{$input};
}