krust is a k-mer counter written in Rust and run from the command line that will output canonical k-mers and their frequency across the records in a fasta file.
Run krust on the test data in the krust Github repo, searching for kmers of length 5, like this:
$ cargo run --release 5 cerevisae.pan.fa > output.tsv
or, searching for kmers of length 21:
$ cargo run --release 21 cerevisae.pan.fa > output.tsv
krust prints to stdout, writing, on alternate lines:
>{frequency}
{canonical k-mer}
>{frequency}
>(canonical k-mer}
...
krust uses rust-bio, rayon, and dashmap.
Future:
A function like fn single_sequence_canonical_kmers(filepath: String, k: usize) {}
Would returns k-mer counts for individual sequences in a fasta file.