Find all words containing characters in UNIX

Question

Given a word W, I want to find all words containing the letters in W from /usr/dict/words. For example, \"bat\" should return \"bat\" and \"tab\" (but not \"table\").

He

Answer 1

So we have the following:

n = length of input word
L = lines in dictionary file

If n tends to be small and L tends to be huge, might we be better off finding all permutations of the input word and looking for those, rather than doing something (like sorting) to all L lines of the dictionary file? (Actually, since finding all permutations of a word is O(n!), and we have to run through the entire dictionary file once for each word, maybe not, but I wrote the code anyway.)

This is Perl - I know you wanted command-line operations but I don't have a way to do that in shell script that's not super-hacky:

sub dedupe {
    my (@list) = @_;
    my (@new_list, %seen_entries, $entry);

    foreach $entry (@list) {
        if (!(defined($seen_entries{$entry}))) {
            push(@new_list, $entry);
            $seen_entries{$entry} = 1;
        }
    }

    return @new_list;
}

sub find_all_permutations {
    my ($word) = @_;
    my (@permutations, $subword, $letter, $rest_of_word, $i);

    if (length($word) == 1) {
        push(@permutations, $word);
    } else {   
        for ($i=0; $i