See also UCLUST sort order Sort sequences by decreasing length. The output file is specified by the ‑fastaout option. The ‑minseqlength option can be used to specify a minimum length to keep. The -relabel prefix option can be used to generate sequential labels for the sorted sequences (requires v6.0.235 or later). The output label is prefixN where N=1, 2, 3 etc. If -sizeout is used, a size annotation will be appended to the sequential label. The -topn N option specifies that no more than N sequences should be output. Example usearch -sortbylength seqs.fasta -fastaout seqs_sorted.fasta -minseqlength 64 |