Simlify split2 prefix

[fgvieira]

This is not a bug, but rather a suggestion. 😄

seqkit subcommands split and split2 have several options to define prefix, depending on how the sequences are split:

      --by-length-prefix string   file prefix for --by-length. The placeholder "{read}" is needed for paired-end files.
      --by-part-prefix string     file prefix for --by-part. The placeholder "{read}" is needed for paired-end files.
      --by-size-prefix string     file prefix for --by-size. The placeholder "{read}" is needed for paired-end files.
      --by-id-prefix string       file prefix for --by-id
      --by-region-prefix string   file prefix for --by-region
      --by-size-prefix string     file prefix for --by-size

Wouldn't it be simpler to just have one prefix (e.g. --out-prefix) for all modes?

[shenwei356]

Reasonable!

[shenwei356]

Ok, added for both commands, and the old options are kept for backward compatibility.

  -P, --out-prefix string         file prefix (it overrides --by-*-prefix). The placeholder "{read}" is
                                  needed for paired-end files.

Example

$ seqkit split2 hairpin.fa -O test -f -s 10000 -e .gz -P yyy_
[INFO] split seqs from hairpin.fa
[INFO] split into 10000 seqs per file
[INFO] write 10000 sequences to file: test/yyy_001.fa.gz
[INFO] write 10000 sequences to file: test/yyy_002.fa.gz
[INFO] write 8645 sequences to file: test/yyy_003.fa.gz

Will tag a new release tomorrow soon.