[EMBOSS] A question about uniform sequence address (USA)

[yezhiqiang at gmail.com]

Hi, dear all,

      As we all know, we can use USA grammar like this:
Format::database:entryname[1:50]. This is referred to as first 1 to 50
residues (nt for dna) of entry "entryname" in database.
     But now I have a sequencial database(eg.  a flatfile or fasta
format sequence file), can we use the entry position (not the entry
name ) to refer the entry? For example, how can I get the 5th sequence
in the flatfile? Can USA handle this kind of request?
    Thanks.