- [SeqKit v2.13.0](https://github.com/shenwei356/seqkit/releases/tag/v2.13.0) - 2026-02-28
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.13.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.13.0)
    - `seqkit`: add support for reading and writing LZ4 compression format.
    - **new command: `seqkit sample2`**: improved `seqkit sample` by [@stahiga](https://github.com/stahiga). [#566](https://github.com/shenwei356/seqkit/pull/566), [#386](https://github.com/shenwei356/seqkit/issues/386)
    - `seqkit seq`:
        - add flags to specify sequences to operate/transform. [#568](https://github.com/shenwei356/seqkit/issues/568)
    - `seqkit shuffle`:
        - add a new option `--tmp-dir`, which can specify tmp dir for FASTA records from stdin or compressed FASTA files. [#562](https://github.com/shenwei356/seqkit/issues/562)
    - `seqkit shuffle/sample`:
        - add a new flag `-r/--non-deterministic`, which uses a time-based seed to **generate non-deterministic (truly random) results**. [#565](https://github.com/shenwei356/seqkit/issues/565)
    - `seqkit restart`:
        - **support specifying the starting sequence of circular genomes**.
    - `seqkit split/split2`:
        - add a new option `-P/--out-prefix` to override `--by-*-prefix`, for simplifying output prefix setting. [#563](https://github.com/shenwei356/seqkit/issues/563)
    - `seqkit bam`:
        - fix a bug [#200](https://github.com/shenwei356/seqkit/issues/200) by @botond-sipos.
    - `seqkit stats`:
        - fix detecting file format type for FASTQ records with empty sequences. [#569](https://github.com/shenwei356/seqkit/issues/569)
- [SeqKit v2.12.0](https://github.com/shenwei356/seqkit/releases/tag/v2.12.0) - 2025-12-04
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.12.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.12.0)
    - `seqkit grep`:
        - `-p/--pattern` accepts empty character (`""`) now. So it's able to **search records with empty IDs or sequences**. [#558](https://github.com/shenwei356/seqkit/issues/558)
    - `seqkit split2`:
        - fix a bug introduced in v2.11.0: `--by-part-prefix` options has no effect. [#554](https://github.com/shenwei356/seqkit/issues/554)
    - `seqkit replace`:
        - `{uuid}`: use the time-sortable UUIDv7 to replace v4.
    - `seqkit stats/fx2tab`:
        - add information about how the average quality is computed. [#448](https://github.com/shenwei356/seqkit/issues/448)
- [SeqKit v2.11.0](https://github.com/shenwei356/seqkit/releases/tag/v2.11.0) - 2025-11-20
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.11.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.11.0)
    - `seqkit`:
        - **fix reading records with both empty id and sequence**. [#550](https://github.com/shenwei356/seqkit/issues/550)
        - check if the output file name equals to one of the input files. [#541](https://github.com/shenwei356/seqkit/issues/541)
    - `seqkit split2`:
        - add a new flag `-N, --seqid-as-filename` to use the first sequence ID as the file name. 
        E.g., using `-N -s 1` is equal to `seqkit split --by-id`, but it's much faster and uses less memory.
    - `seqkit head`:
        - add a new flag `-l, --length` to print heading FASTA/Q records with total sequence length >= N, e.g., `-l 2G`.
    - `seqkit replace`:
        - add a new replacement symbol `{uuid}` for random UUID. [#552](https://github.com/shenwei356/seqkit/issues/552)
- [SeqKit v2.10.1](https://github.com/shenwei356/seqkit/releases/tag/v2.10.1) - 2025-08-19
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.10.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.10.1)
    - `seqkit seq`:
        - fix validating sequences: it failed to report an error when the invalid sequence is not the last one in the input. [#536](https://github.com/shenwei356/seqkit/issues/536)
    - `seqkit stats`:
        - fix decimal places of some fields when using `-T`.
    - `seqkit fx2tab`:
        - fix the calculation of GC content (`--gc`). Previously, the denominator was the total sequence length, which could lead to inaccuracies due to the potential presence of gaps in the sequence. [#515](https://github.com/shenwei356/seqkit/issues/515)
    - `seqkit sample`:
        - fix `-n` for in-memory mode. [#518](https://github.com/shenwei356/seqkit/issues/518)
    - `seqkit subseq`:
        - fix the bug that subseq --feature is not case insensitive. [#523](https://github.com/shenwei356/seqkit/issues/523)
    - `seqkit grep/locate/mutate`:
        - update help message for `-p/--pattern`, to show how to set multiple values. [#527](https://github.com/shenwei356/seqkit/pull/527) by @corneliusroemer
- [SeqKit v2.10.0](https://github.com/shenwei356/seqkit/releases/tag/v2.10.0) - 2025-03-12
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.10.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.10.0)
    - `seqkit`:
        - add a global flag `--skip-file-check`: skip input file checking when given a file list if you believe these files do exist.
        It helps to reduce file checking time when given a huge number of sequence files.
    - `seqkit split2`:
        - fix prefix checking when paired-end files are given. [#512](https://github.com/shenwei356/seqkit/issues/512)
    - `seqkit stat`:
        - do not compute GC content and N's for protein sequence. [#497](https://github.com/shenwei356/seqkit/issues/497)
    - `seqkit grep`:
        - add early exit for `--delete-matched` when no patterns remain [#505](https://github.com/shenwei356/seqkit/pull/505) by @sawyerknoblich
    - `seqkit concat`:
        - add an option `-F/--fill` to use a sequence of "-" for IDs missing in some files, can be used in MSA results. [#510](https://github.com/shenwei356/seqkit/issues/510)
- [SeqKit v2.9.0](https://github.com/shenwei356/seqkit/releases/tag/v2.9.0) - 2024-11-01
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.9.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.9.0)
    - `seqkit`:
        - **Fix sequence ID parsing with the default regular expression (in this case, we actually use bytes.Index instead) for a rare case: "xxx\tyyy zzz" was wrongly parsed as "xxx\tyyy"**. [#486](https://github.com/shenwei356/seqkit/issues/486)
    - `seqkit locate`:
        - **Fix `-G/--non-greedy` for tandem repeats**, e.g., ATTCGATTCGATTCG (ATTCGx3).
    - `seqkit grep/subseq`:
        - Fix negative regions longer than sequence length. [#479](https://github.com/shenwei356/seqkit/issues/479).
    - `seqkit stats`:
        - Add an extra column `sum_n` to count the number of ambiguous characters. [#490](https://github.com/shenwei356/seqkit/issues/490)
- [SeqKit v2.8.2](https://github.com/shenwei356/seqkit/releases/tag/v2.8.2) - 2024-05-17
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.8.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.8.2)
    - `seqkit amplicon`:
        - Fix a big introduced in v2.7.0. When more than one pairs of primers are given, only the last one is used. [#457](https://github.com/shenwei356/seqkit/issues/457)
    - `seqkit translate`:
        - Add option `-e/--skip-translate-errors` to skip translate error and output empty sequence. [#458](https://github.com/shenwei356/seqkit/pull/458)
    - `seqkit split`:
        - Add flag `-I/--ignore-case` for `-i/--by-id`. [#462](https://github.com/shenwei356/seqkit/issues/462)
- [SeqKit v2.8.1](https://github.com/shenwei356/seqkit/releases/tag/v2.8.1) - 2024-04-07
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.8.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.8.1)
    - `seqkit sana`:
        - Add support for FASTQ files with IDs in the separator (`+`, 3rd) lines.. [#446](https://github.com/shenwei356/seqkit/pull/446), [#429](https://github.com/shenwei356/seqkit/issues/429), [#408](https://github.com/shenwei356/seqkit/issues/408)
    - `seqkit subseq`:
        - Add some docs to show how to keep the original order of sequences when extracting with BED: compress the input FASTA file. [#451](https://github.com/shenwei356/seqkit/issues/451)
- [SeqKit v2.8.0](https://github.com/shenwei356/seqkit/releases/tag/v2.8.0) - 2024-01-31
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.8.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.8.0)
    - `seqkit stats`:
        - Add column `N50_num`, an alias of L50, [#15](https://github.com/shenwei356/seqkit/issues/15).
    - `seqkit seq/locate/fish/watch`:
        - Removing the flag `-V/--validate-seq-length`. Now the whole sequence will be checked if `-v/--validate-seq` is given.
    - `seqkit amplicon`:
        - Fix the speed problem, introduced in v2.7.0. [#439](https://github.com/shenwei356/seqkit/issues/439).
        - Slightly faster by reusing objects.
    - `seqkit seq`:
        - Change the threshold sequence length for parallelizing complement sequence computation, 1kb->1Mb.
- [SeqKit v2.7.0](https://github.com/shenwei356/seqkit/releases/tag/v2.7.0) - 2024-01-31
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.7.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.7.0)
    - `seqkit`:
        - Grouping subcommands in help message, which is intuitive for beginners.
    - `seqkit grep`:
        - New flag: `-D/--allow-duplicated-patterns` for outputting records multiple times when duplicated patterns are given. [#427](https://github.com/shenwei356/seqkit/issues/427)
    - `seqkit subseq`:
        - Use the ID regular expression from the option `--id-regexp` to create FASTA index file. This solves the panic happened for sequences containing tabs in the headers. [#432](https://github.com/shenwei356/seqkit/issues/432)
    - `seqkit split/sort/shuffle`:
        - When using the two-pass mode (`-2/--two-pass`), replace possible tabs in the sequence header.
    - `seqkit rmdup`:
        - Write an empty file of duplicate numbers and lists of IDs even if there's no duplicates when using `-D/--dup-num-file`. [#436](https://github.com/shenwei356/seqkit/issues/436)
    - `seqkit stats`:
        - New flag `-S/--skip-file-check` to skip input file checking when given files or a file list. It's very useful if you run it with millions of files.
- [SeqKit v2.6.1](https://github.com/shenwei356/seqkit/releases/tag/v2.6.1) - 2023-11-18
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.6.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.6.1)
    - `seqkit`:
        - fix panic of nil pointer introduced in v2.6.0, which happens when handling multiple input files and some of them have file sizes of zero.
    - `seqkit seq`:
        - fix panic (close of closed channel) when using `-v` to checking sequences.
- [SeqKit v2.6.0](https://github.com/shenwei356/seqkit/releases/tag/v2.6.0) - 2023-11-09
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.6.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.6.0)
    - `seqkit`:
        - add the shortcut `-X` for the flag `--infile-list`.
    - `seqkit common`:
        - **add a new flag `-e/--check-embedded-seqs` for detecting embedded sequences.**
        - for matching by sequences: reduced the memory occupation and corrected numbers in the log. [#416](https://github.com/shenwei356/seqkit/issues/416)
    - `seqkit stat`:
        - add a new column `AvgQual` for average quality score. [#411](https://github.com/shenwei356/seqkit/issues/411)
    - `seqkit split2`:
        - fix the panic for invalid input.
    - `seqkit subseq`:
        - add a new flag `-R/--region-coord` for appending coordinates to sequence ID for `-r/--region`. [#413](https://github.com/shenwei356/seqkit/issues/413)
    - `seqkit locate`:
        - add a new flag `-s/--max-len-to-show` to show at most X characters for the search pattern or matched sequences.
    - `seqkit seq`:
        - change the nucleotide color theme. [#412](https://github.com/shenwei356/seqkit/pull/412)
- [SeqKit v2.5.1](https://github.com/shenwei356/seqkit/releases/tag/v2.5.1) - 2023-08-09
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.5.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.5.1)
    - `seqkit stats`:
        - **fix a concurrency bug (file name error) introduced in v2.5.0**. [#405](https://github.com/shenwei356/seqkit/issues/405)
    - `seqkit subseq`:
        - sequence/chromosome IDs are case-sensitive now. [#400](https://github.com/shenwei356/seqkit/issues/400)
- [SeqKit v2.5.0](https://github.com/shenwei356/seqkit/releases/tag/v2.5.0) - 2023-07-16
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.5.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.5.0)
    - new command `seqkit merge-slides`: merge sliding windows generated from seqkit sliding. [#390](https://github.com/shenwei356/seqkit/issues/390)
    - `seqkit stats`:
        - added a new flag `-N/--N` for appending other N50-like stats as new columns. [#393](https://github.com/shenwei356/seqkit/issues/393)
        - added a progress bar for > 1 input files.
        - write the result of each file immediately (no output buffer) when using `-T/--tabular`.
    - `seqkit translate`:
        - add options `-s/--out-subseqs` and `-m/--min-len` to write ORFs longer than `x` amino acids as individual records. [#389](https://github.com/shenwei356/seqkit/issues/389)
    - `seqkit sum`:
        - do not remove possible '*' by default and delete confusing warnings. Thanks to @photocyte. [#399](https://github.com/shenwei356/seqkit/issues/399)
        - added a progress bar for > 1 input files.
    - `seqkit pair`:
        - remove the restriction of requiring FASTQ format, i.e., FASTA files are also supported.
    - `seqkit seq`:
        - update help messages. [#387](https://github.com/shenwei356/seqkit/issues/387)
    - `seqkit fxtab`:
        - faster alphabet computation (`-a/--alphabet`) with a new data structure. Thanks to @elliotwutingfeng [#388](https://github.com/shenwei356/seqkit/pull/388)
    - `seqkit subseq`:
        - accept reverse coordinates in BED/GTF. [#392](https://github.com/shenwei356/seqkit/issues/392)
- [SeqKit v2.4.0](https://github.com/shenwei356/seqkit/releases/tag/v2.4.0) - 2023-03-17
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.4.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.4.0)
    - `seqkit`:
        - **support `bzip2` format**. [#361](https://github.com/shenwei356/seqkit/issues/361)
        - support setting compression level for `gzip`, `zstd`, and `bzip2` format via `--compress-level`. [#320](https://github.com/shenwei356/seqkit/issues/320)
        - the global flag `--infile-list` accepts stdin (`-`) now.
        - wrap the help message of flags.
    - `seqkit locate`:
        - **do not remove embeded regions when searching with regular expressions**. [#368](https://github.com/shenwei356/seqkit/issues/368)
    - `seqkit amplicon`:
        - fix BED coordinates for amplicons found in the minus strand. [#367](https://github.com/shenwei356/seqkit/issues/367)
    - `seqkit split`:
        - fix forgetting to add extension for `--two-pass`. [#332](https://github.com/shenwei356/seqkit/issues/332)
    - `seqkit stats`:
        - fix compute Q1 and Q3 of sequence length for one record. [#353](https://github.com/shenwei356/seqkit/issues/353)
    - `seqkit grep`:
        - fix count number (`-C`) for matching with mismatch (`-m > 0`). [#370](https://github.com/shenwei356/seqkit/issues/370)
    - `seqkit replace`:
        - **add some flags to match partly records to edit**; these flags are transplanted from `seqkit grep`. [#348](https://github.com/shenwei356/seqkit/issues/348)
    - `seqkit faidx`:
        - **allow empty lines at the end of sequences**.
    - `seqkit faidx/sort/shuffle/split/subseq`:
        - **new flag `-U/--update-faidx`: update the FASTA index file if it exists, to guarantee the index file matches the FASTA files**. [#364](https://github.com/shenwei356/seqkit/issues/364)
        - improve log info and update help message. [#365](https://github.com/shenwei356/seqkit/issues/365)
    - `seqkit seq`: 
        - allow filtering sequences of length zero. thanks to @penglbio.
    - `seqkit rename`:
        - new flag `-s/--separator` for setting separator between original ID/name and the counter (default "_"). [#360](https://github.com/shenwei356/seqkit/issues/360)
        - new flag `-N/--start-num` for setting starting count number for duplicated IDs/names (default 2). [#360](https://github.com/shenwei356/seqkit/issues/360)
        - new flag `-1/--rename-1st-rec` for renaming the first record as well. [#360](https://github.com/shenwei356/seqkit/issues/360)
        - do not append space if there's no description after the sequene ID.
    - `seqkit sliding`:
        - new flag `-S/--suffix` for change the suffix added to the sequence ID (default: "_sliding").
- [SeqKit v2.3.1](https://github.com/shenwei356/seqkit/releases/tag/v2.3.1) - 2022-09-22
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.3.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.3.1)
    - `seqkit grep/locate`: fix bug of FMIndex building for empty sequences. [#321](https://github.com/shenwei356/seqkit/issues/321)
    - `seqkit split2`: fix bug of splitting two FASTA files. [#325](https://github.com/shenwei356/seqkit/issues/325)
    - `seqkit faidx`: `--id-regexp` works now.
- [SeqKit v2.3.0](https://github.com/shenwei356/seqkit/releases/tag/v2.3.0) - 2022-08-12
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.3.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.3.0)
    - `seqkit grep/rename`:
        - *reduce memory comsumption for a lot of searching patterns, and it's faster*. [#305](https://github.com/shenwei356/seqkit/issues/305)
        - 2X faster `-s/--by-seq`.
    - `seqkit split`
        - fix outputting an empty file when the number of sequence equal to the split size. [#293](https://github.com/shenwei356/seqkit/issues/293)
        - add options to set output file prefix and extention. [#296](https://github.com/shenwei356/seqkit/issues/296)
    - `seqkit split2`
        - reduce memory consumption. [#304](https://github.com/shenwei356/seqkit/issues/304)
        - add options to set output file prefix
    - `seqkit stats`:
        - add GC content. [#294](https://github.com/shenwei356/seqkit/issues/294)
- [SeqKit v2.2.0](https://github.com/shenwei356/seqkit/releases/tag/v2.2.0) - 2022-03-14
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.2.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.2.0)
    - `seqkit`:
        - **add support of `xz` and `zstd` input/output formats**. [#274](https://github.com/shenwei356/seqkit/issues/274)
        - fix panic when reading records with header of `ID` + blanks.
    - **new command `seqkit sum`: computing message digest for all sequences in FASTA/Q files**.
      The idea comes from @photocyte and the format borrows from [seqhash](https://github.com/TimothyStiles/poly/tree/prime/seqhash) [#262](https://github.com/shenwei356/seqkit/issues/262)
    - new command `seqkit fa2fq`: retrieving corresponding FASTQ records by a FASTA file
    - `seqkit split2`:
        - new flag `-e/--extension` for forcing compresson or changing compression format. [#276](https://github.com/shenwei356/seqkit/issues/276)
        - support changing output prefix via `-o/--out-file`. [#275](https://github.com/shenwei356/seqkit/issues/275)
    - `seqkit concat`: 
        - fix handling of multiple seqs with the same ID in one file. [#269](https://github.com/shenwei356/seqkit/issues/269)
        - performaning out/full join. [#270](https://github.com/shenwei356/seqkit/issues/270)
        - preserve the comments. [#271](https://github.com/shenwei356/seqkit/issues/271)
    - `seqkit locate`:
        - parallelizing `-F/--use-fmi` and `-m` for large number of search patterns.
    - `seqkit amplicon`:
        - new flag `-M/--output-mismatches` to append the total mismatches and mismatches of 5' end and 3' end. [#286](https://github.com/shenwei356/seqkit/issues/286)
    - `seqkit grep`:
        - detect FASTA/Q symbol `@` and `>` in the searching patterns and show warnings.
        - add new flag `-C/--count`, like `grep -c` in GNU grep. [#267](https://github.com/shenwei356/seqkit/issues/267)
    - `seqkit range`:
        - support removing leading 100 seqs (`seqkit range -r 101:-1` == `tail -n +101`). [#279](https://github.com/shenwei356/seqkit/issues/279)
    - `seqkit subseq`:
        - report error when no options were given.
    - update doc:
        - `seqkit head`: add doc for "seqkit tail": `seqkit range -N:-1 seqs.fasta`. [#272](https://github.com/shenwei356/seqkit/issues/272)
        - `seqkit rmdup`: add the note of only the first record being saved for duplicates. [#265](https://github.com/shenwei356/seqkit/issues/265)
- [SeqKit v2.1.0](https://github.com/shenwei356/seqkit/releases/tag/v2.1.0) - 2021-11-15
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.1.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.1.0)
    - `seqkit seq`:
        - **fix filtering by average quality `-Q/-R`**. [#257](https://github.com/shenwei356/seqkit/issues/257)
    - `seqkit convert`:
        - fix quality encoding checking, change default value of `-N/--thresh-B-in-n-most-common` from `4` to `2`. 
        [#254](https://github.com/shenwei356/seqkit/issues/254) and [#239](https://github.com/shenwei356/seqkit/issues/239])
    - `seqkit split`:
        - fix writing an extra empty file when using `--two-pass`[#244](https://github.com/shenwei356/seqkit/issues/244)
    - `seqkit subseq`:
        - fix `--bed` which fail to recognize strand `.`.
    - `seqkit fq2fa`: 
        - faster, and do not wrap sequences.
    - `seqkit grep/locate/mutate`:
        - detect unquoted comma and show warning message, e.g., `-p 'A{2,}'`. [#250](https://github.com/shenwei356/seqkit/issues/250)
- [SeqKit v2.0.0](https://github.com/shenwei356/seqkit/releases/tag/v2.0.0) - 2021-08-27
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v2.0.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v2.0.0)
    - **Performance improvements**
        - `seqkit`:
            - **faster FASTA/Q reading and writing, especially on FASTQ**, see the [benchmark](https://github.com/shenwei356/bio/tree/1e130b6b973e5321bc0e508316716f763cd6f304#fastaq-reading-and-writing).
                - reading (plain text): 4X faster. `seqkit stats dataset_C.fq`
                - reading (gzip files): 45% faster. `seqkit stats dataset_C.fq.gz`
                - reading + writing (plain text): 3.5X faster. `seqkit grep -p . -v  dataset_C.fq -o t`
                - reading + writing (gzip files): 2.2X faster. `seqkit grep -p . -v  dataset_C.fq.gz -o t.gz`
            - **change default value of `-j/--threads` from 2 to 4**, which is faster for writting gzip files.
        - `seqkit seq`:
            - **fix writing speed, which was slowed down in v0.12.1**.
    - **Breaking changes**
        - `seqkit grep/rmdup/common`: 
            - **consider reverse complement sequence by default for comparing by sequence**, add flag `-P/--only-positive-strand`. [#215](https://github.com/shenwei356/seqkit/issues/215)
        - `seqkit rename`:
            - **rename ID only, do not append original header to new ID**. [#236](https://github.com/shenwei356/seqkit/issues/236)
        - `seqkit fx2tab`:
            - for `-s/--seq-hash`: outputing MD5 instead of hash value (integers) of xxhash. [#219](https://github.com/shenwei356/seqkit/issues/219)
    - **Bugfixes**
        - `seqkit seq`:
            - **fix failing to output gzipped format for file name with extension of `.gz` since v0.12.1**.
        - `seqkit tab2fx`:
            - fix bug for very long sequences. [#214](https://github.com/shenwei356/seqkit/issues/214)
        - `seqkit fish`:
            - fix range check. [#213](https://github.com/shenwei356/seqkit/issues/213)
        - `seqkit grep`:
            - it's not exactly a bug: forgot to use multi-threads for `-m` > 0.
    - **New features/enhancements**
        - `seqkit grep`: 
            - allow empty pattern files.
        - `seqkit faidx`:
            - support region with `begin > end`, i.e., **returning reverse complement sequence**
            - add new flag `-l/--region-file`:  file containing a list of regions.
        - `seqkit fx2tab`:
            - new flag `-Q/--no-qual` for disabling outputing quality even for FASTQ file. [#221](https://github.com/shenwei356/seqkit/issues/221)
        - `seqkit amplicon`:
            - new flag `-u/--save-unmatched` for saving records that do not match any primer.
        - `seqkit sort`:
            - new flag `-b/--by-bases` for sorting by non-gap bases, for multiple sequence alignment files.[#216](https://github.com/shenwei356/seqkit/issues/216)
- [SeqKit v0.16.1](https://github.com/shenwei356/seqkit/releases/tag/v0.16.1) - 2021-05-20
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.16.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.16.1)
    - `seqkit shuffle --two-pass`: fix bug introduced in [#173](https://github.com/shenwei356/seqkit/issues/173) . [#209](https://github.com/shenwei356/seqkit/issues/209)
    - `seqkit pair`: fix a dangerous bug: when input files are not in current directory, input files were overwritten.
- [SeqKit v0.16.0](https://github.com/shenwei356/seqkit/releases/tag/v0.16.0) - 2021-04-16
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.16.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.16.0)
    - new command `seqkit head-genome`:
        - print sequences of the first genome with common prefixes in name
    - `seqkit grep/locate/amplicon -m`
        - *much faster (300-400x) searching with mismatch allowed* by optimizing FM-indexing and parallelization.
        - new flag `-I/--immediate-output`.
    - `seqkit grep/locate`:
        - fix bug of `-m` when querying contains letters not in alphabet, usually for protein sequences. [#178](https://github.com/shenwei356/seqkit/issues/178), [#179](https://github.com/shenwei356/seqkit/issues/179)
        - onply search on positive strand when searching unlimited or protein sequences.
    - `seqkit locate`:
        - removing debug info for `-r` introduced in a0f6b6e. [#180](https://github.com/shenwei356/seqkit/issues/180)
    - `seqkit amplicon`:
        - fix bug of `-m`, when mismatch is allowed.
    - `seqkit fx2tab`:
        - new flag `-C/--base-count` for counting bases. [#183](https://github.com/shenwei356/seqkit/issues/183)
    -  `seqkit tab2fx`:
        -  fix a rare bug. [#197](https://github.com/shenwei356/seqkit/issues/197)
    - `seqkit subseq`:
        - fix bug for BED with empty columns. [#195](https://github.com/shenwei356/seqkit/issues/195)
    - `seqkit genautocomplete`: 
        - **support bash|zsh|fish|powershell**.
- [SeqKit v0.15.0](https://github.com/shenwei356/seqkit/releases/tag/v0.15.0) - 2021-01-12
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.15.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.15.0)
    - `seqkit grep/locate`: update help message.
    - `seqkit grep`: **search on both strand when searching by sequence**.
    - `seqkit split2`: fix redundant log when using `-s`.
    - `seqkit bam`: new field `RightSoftClipSeq`. [#172](https://github.com/shenwei356/seqkit/pull/172)
    - `seqkit sample -2`: remove extra `\n`. [#173](https://github.com/shenwei356/seqkit/issues/173)
    - `seqkit split2 -l`: fix bug for splitting by accumulative length, this bug occurs when the first record is longer than `-l`, no sequences are lost.
- [SeqKit v0.14.0](https://github.com/shenwei356/seqkit/releases/tag/v0.14.0) - 2020-10-30
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.14.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.14.0)
    - new command `seqkit pair`: match up paired-end reads from two fastq files, faster than fastq-pair.
    - `seqkit translate`: new flag `-F/--append-fram` for optional adding frame info to ID. [#159](https://github.com/shenwei356/seqkit/issues/159)
    - `seqkit stats`: reduce memory usage when using `-a` for calculating N50. [#153](https://github.com/shenwei356/seqkit/issues/153)
    - `seqkit mutate`: fix inserting sequence `-i/--insertion`, 
       this bug occurs when `insert site` is big in some cases, don't worry if no error reported.
    - `seqkit replace`:
        - new flag `-U/--keep-untouched`: do not change anything when no value found for the key (only for sequence name).
        - do no support editing FASTQ sequence.
    - `seqkit grep/locate`: new flag `--circular` for supporting circular genome. [#158](https://github.com/shenwei356/seqkit/issues/158)
- [SeqKit v0.13.2](https://github.com/shenwei356/seqkit/releases/tag/v0.13.2) - 2020-07-13
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.13.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.13.2)
    - `seqkit sana`: fix bug causing hanging on empty files. [#149](https://github.com/shenwei356/seqkit/pull/149)
- [SeqKit v0.13.1](https://github.com/shenwei356/seqkit/releases/tag/v0.13.1) - 2020-07-09
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.13.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.13.1)
    - `seqkit sana`: fix bug causing hanging on empty files. [#148](https://github.com/shenwei356/seqkit/pull/148)
- [SeqKit v0.13.0](https://github.com/shenwei356/seqkit/releases/tag/v0.13.0) - 2020-07-07
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.13.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.13.0)
    - `seqkit`: fix a rare FASTA/Q parser bug. [#127](https://github.com/shenwei356/seqkit/issues/127)
    - `seqkit seq`: output sequence or quality in single line when `-s/--seq` or `-q/--qual` is on. [#132](https://github.com/shenwei356/seqkit/issues/132)
    - `seqkit translate`: delete debug info, [#133](https://github.com/shenwei356/seqkit/issues/133), and fix typo. [#134](https://github.com/shenwei356/seqkit/issues/134)
    - `seqkit split2`: tiny performance improvement. [#137](https://github.com/shenwei356/seqkit/issues/137)
    - `seqkit stats`: new flag `-i/--stdin-label` for replacing default "-" for stdin. [#139](https://github.com/shenwei356/seqkit/issues/139)
    - `seqkit fx2tab`: new flag `-s/--seq-hash` for printing hash of sequence (case sensitive). [#144](https://github.com/shenwei356/seqkit/issues/144)
    - `seqkit amplicon`:
        - fix bug of missing searching reverse strand. [#140](https://github.com/shenwei356/seqkit/issues/140)
        - supporting degenerate bases now. [#83](https://github.com/shenwei356/seqkit/issues/83)
        - new flag `-p/--primer-file` for reading list of primer pairs. [#142](https://github.com/shenwei356/seqkit/issues/142)
        - new flag `--bed` for outputing in BED6+1 format. [#141](https://github.com/shenwei356/seqkit/issues/141)
    - New features and improvements by [@bsipos](https://github.com/bsipos). [#130](https://github.com/shenwei356/seqkit/pull/130), [#147](https://github.com/shenwei356/seqkit/pull/147)
        - new command `seqkit scat`, for real-time robust concatenation of fastx files. 
        - Rewrote the parser behind the `sana` subcommand, now it supports robust parsing of fasta file as well.
        - Added a "toolbox" feature to the `bam` subcommand (`-T`), which is a collection of filters acting on streams of BAM records configured through a YAML string (see the docs for more).
        - Added the `SEQKIT_THREADS` environmental variable to override the default number of threads.
- [SeqKit v0.12.1](https://github.com/shenwei356/seqkit/releases/tag/v0.12.1) - 2020-04-21
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.12.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.12.1)
    - `seqkit bam`: add colorised and pretty printed output, by [@bsipos](https://github.com/bsipos). [#110](https://github.com/shenwei356/seqkit/pull/110)
    - `seqkit locate/grep`: fix bug of `-m`, when query contains letters not in subject sequences. [#124](https://github.com/shenwei356/seqkit/issues/124)
    - `seqkit split2`: new flag `-l/--by-length` for splitting into chunks of N bases.
    - `seqkit fx2tab`:
        - new flag `-I/--case-sensitive` for calculating case sensitive base content. [#108](https://github.com/shenwei356/seqkit/issues/108)
        - add missing column name for averge quality for `-H -q`. [#115](https://github.com/shenwei356/seqkit/issues/115)
        - fix output of `-n/--only-name`, do not write empty columns of sequence and quality. [#104](https://github.com/shenwei356/seqkit/issues/104), [#115](https://github.com/shenwei356/seqkit/issues/115)
    - `seqkit seq`: new flag `-k/--color`: colorize sequences.
- [SeqKit v0.12.0](https://github.com/shenwei356/seqkit/releases/tag/v0.12.0) - 2020-02-18
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.12.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.12.0)
    - `seqkit`:
        - fix checking input file existence.
        - new global flag `--infile-list` for long list of input files, if given, they are appended to files from cli arguments.
    - `seqkit faidx`: supporting "truncated" (no ending newline charactor) file.
    - `seqkit seq`:
        - **do not force switching on `-g` when using `-m/-M`**.
        - show recommendation if flag `-t/--seq-type` is not DNA/RNA when computing complement sequence. [#103](https://github.com/shenwei356/seqkit/issues/103)
    - `seqkit translate`: supporting multiple frames. [#96](https://github.com/shenwei356/seqkit/issues/96)
    - `seqkit grep/locate`:
        - add detection and warning for space existing in search pattern/sequence.
        - **speed improvement (2X) for `-m/--max-mismatch`**. [shenwei356/bwt/issues/3](https://github.com/shenwei356/bwt/issues/3)
    - `seqkit locate`:
        - new flag `-M/--hide-matched` for hiding matched sequences. [#98](https://github.com/shenwei356/seqkit/issues/98)
        - **new flag `-r/--use-regexp` for explicitly using regular expression, so improve speed of default `index` operation. And you have to switch this on if using regexp now**.
        [#101](https://github.com/shenwei356/seqkit/issues/101)
        - **new flag `-F/--use-fmi` for improving search speed for lots of sequence patterns**.
    - `seqkit rename`: making IDs unique across multiple files, and can write into multiple files. [#100](https://github.com/shenwei356/seqkit/issues/100)
    - `seqkit sample`: fix stdin checking for flag `-2`. [#102](https://github.com/shenwei356/seqkit/issues/102).
    - `seqkit rename/split/split2`: fix detection of existed outdir.
    - `split split`: fix bug of `seqkit split -i -2` and parallizing it.
    - `seqkit version`: checking update is optional (`-u`).
- [SeqKit v0.11.0](https://github.com/shenwei356/seqkit/releases/tag/v0.11.0) - 2019-09-25
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.11.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.11.0)
    - `seqkit`: fix hanging when reading from truncated gzip file.
    - new commands:
        - `seqkit amplicon`: retrieve amplicon (or specific region around it) via primer(s).
    - [new commands by @bsipos](https://github.com/shenwei356/seqkit/pull/81):
        - `seqkit watch`: monitoring and online histograms of sequence features.
        - `seqkit sana`: sanitize broken single line fastq files.
        - `seqkit fish`: look for short sequences in larger sequences using local alignment.
        - `seqkit bam`: monitoring and online histograms of BAM record features.
    - `seqkit grep/locate`: reduce memory occupation when using flag `-m/--max-mismatch`.
    - `seqkit seq`: fix panic of computing complement sequence for long sequences containing illegal letters without flag `-v` on. [#84](https://github.com/shenwei356/seqkit/issues/84)
- [SeqKit v0.10.2](https://github.com/shenwei356/seqkit/releases/tag/v0.10.2) - 2019-07-30
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.10.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.10.2)
    - `seqkit`: fix bug of parsing sequence ID delimited by tab (`\t`). [#78](https://github.com/shenwei356/seqkit/issues/78)
    - `seqkit grep`: better logic of `--delete-matched`.
    - `seqkit common/rmdup/split`: use xxhash to replace MD5 when comparing with sequence, discard flag `-m/--md5`.
    - `seqkit stats`: new flag `-b/--basename` for outputting basename instead of full path.
- [SeqKit v0.10.1](https://github.com/shenwei356/seqkit/releases/tag/v0.10.1) - 2019-02-27
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.10.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.10.1)
    - `seqkit fx2tab`: new option `-q/--avg-qual` for outputting average read quality. [#60](https://github.com/shenwei356/seqkit/issues/60)
    - `seqkit grep/locate`: fix support of `X` when using `-d/--degenerate`. [#61](https://github.com/shenwei356/seqkit/issues/61)
    - `seqkit translate`:
        - new flag `-M/--init-codon-as-M` to translate initial codon at beginning to 'M'. [#62](https://github.com/shenwei356/seqkit/issues/62)
        - translates `---` to `-` for aligned DNA/RNA, flag `-X` needed. [#63](https://github.com/shenwei356/seqkit/issues/63)
        - supports codons containing ambiguous bases, e.g., `GGN->G`, `ATH->I`. [#64](https://github.com/shenwei356/seqkit/issues/64)
        - new flag `-l/--list-transl-table` to show details of translate table N
        - new flag `-l/--list-transl-table-with-amb-codons` to show details of translate table N (including ambigugous codons)
    - `seqkit split/split2`, fix bug of ignoring `-O` when reading from stdin.
- [SeqKit v0.10.0](https://github.com/shenwei356/seqkit/releases/tag/v0.10.0) - 2018-12-24
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.10.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.10.0)
    - `seqkit`: report error when input is directory.
    - new command `seqkit mutate`: edit sequence (point mutation, insertion, deletion).
- [SeqKit v0.9.3](https://github.com/shenwei356/seqkit/releases/tag/v0.9.3) - 2018-12-02
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.9.3/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.9.3)
    - `seqkit stats`: fix panic for empty file. [#57](https://github.com/shenwei356/seqkit/issues/57)
    - `seqkit translate`: add flag `-x/--allow-unknown-codon` to translate unknown codon to `X`.
- [SeqKit v0.9.2](https://github.com/shenwei356/seqkit/releases/tag/v0.9.2) - 2018-11-16
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.9.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.9.2)
    - `seqkit`: stricter checking for value of global flag `-t/--seq-type`.
    - `seqkit sliding`: fix bug for flag `-g/--greedy`. [#54](https://github.com/shenwei356/seqkit/issues/54)
    - `seqkit translate`: fix bug for frame < 0. [#55](https://github.com/shenwei356/seqkit/issues/55)
    - `seqkit seq`: add TAB to default blank characters (flag `-G/--gap-letters`), and fix filter result when using flag `-g/--remove-gaps` along with `-m/--min-len` or `-M/--max-len`
- [SeqKit v0.9.1](https://github.com/shenwei356/seqkit/releases/tag/v0.9.1) - 2018-10-12
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.9.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.9.1)
    - `seqkit faidx`: fix bug of retrieving subsequence with multiple regions on same sequence. [#48](https://github.com/shenwei356/seqkit/issues/48)
    - `seqkit sort/shuffle/split`: fix bug when using `-2/--two-pass` to process `.gz` files. [#52](https://github.com/shenwei356/seqkit/issues/52)
- [SeqKit v0.9.0](https://github.com/shenwei356/seqkit/releases/tag/v0.9.0) - 2018-09-26
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.9.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.9.0)
    - `seqkit`: better handle of empty file, no error message shown. [#36](https://github.com/shenwei356/seqkit/issues/36)
    - new subcommand `seqkit split2`: split sequences into files by size/parts (FASTA, PE/SE FASTQ).  [#35](https://github.com/shenwei356/seqkit/issues/35)
    - new subcommand `seqkit translate`: translate DNA/RNA to protein sequence. [#28](https://github.com/shenwei356/seqkit/issues/28)
    - `seqkit sort`: fix bug when using `-2 -i`, and add support for sorting in natural order. [#39](https://github.com/shenwei356/seqkit/issues/39)
    - `seqkit grep` and `seqkit locate`: add experimental support of mismatch when searching subsequences. [#14](https://github.com/shenwei356/seqkit/issues/14)
    - `seqkit stats`: add stats of Q20 and Q30 for FASTQ. [#45](https://github.com/shenwei356/seqkit/issues/45)
- [SeqKit v0.8.1](https://github.com/shenwei356/seqkit/releases/tag/v0.8.1) - 2018-06-29
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.8.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.8.1)
    - `seqkit`: do not call `pigz` or `gzip` for decompressing gzipped file any more. But you can still utilize `pigz` or `gzip` by `pigz -d -c seqs.fq.gz | seqkit xxx`.
    - `seqkit subseq`: fix bug of missing quality when using `--gtf` or `--bed`
    - `seqkit stats`: parallelize counting files, it's much faster for lots of small files, especially for files on SSD
- [SeqKit v0.8.0](https://github.com/shenwei356/seqkit/releases/tag/v0.8.0) - 2018-03-22
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.8.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.8.0)
  - `seqkit`, **stricter FASTA/Q format requirement**, i.e., must starting with `>` or `@`.
  - `seqkit`, *fix output format for FASTQ files containing zero-length records*, yes this [happens](https://github.com/lh3/seqtk/issues/109).
  - `seqkit`, add amino acid code `O` (pyrrolysine) and `U` (selenocysteine).
  - `seqkit replace`, *add flag `--nr-width` to fill leading 0s for `{nr}`*, useful for preparing sequence submission (">strain_00001 XX", ">strain_00002 XX").
  - `seqkit subseq`, require BED file to be tab-delimited.
- [SeqKit v0.7.2](https://github.com/shenwei356/seqkit/releases/tag/v0.7.2) - 2017-12-03
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.7.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.7.2)
    - `seqkit tab2fx`: fix a concurrency bug that occurs in low proprobability
    when only 1-column data provided.
    - `seqkit stats`: add quartiles of sequence length
    - `seqkit faidx`: add support for retrieving subsequence using seq ID and region,
    which is similar with "samtools faidx" but has some extra features
- [SeqKit v0.7.1](https://github.com/shenwei356/seqkit/releases/tag/v0.7.1) - 2017-09-22
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.7.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.7.1)
    - `seqkit convert`: fix bug of read quality containing only 3 or less values.  [shenwei356/bio/issues/3](https://github.com/shenwei356/bio/issues/3)
    - `seqkit stats`: add option `-T/--tabular` to output in machine-friendly tabular format.   [#23](https://github.com/shenwei356/seqkit/issues/23)
    - `seqkit common`: increase speed and decrease memory occupation, and add some notes.
    - fix some typos. [#22](https://github.com/shenwei356/seqkit/issues/22)
    - suggestion: please **install [pigz](http://zlib.net/pigz/) to gain better parsing performance for gzipped data**.
- [SeqKit v0.7.0](https://github.com/shenwei356/seqkit/releases/tag/v0.7.0) - 2017-08-12
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.7.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.7.0)
    - add new command `convert` for converting FASTQ quality encoding between Sanger, Solexa and Illumina. Thanks suggestion from [@cviner](https://github.com/cviner) ( [#18](https://github.com/shenwei356/seqkit/issues/18)). [usage & example](http://bioinf.shenwei.me/seqkit/usage/#convert).
    - add new command `range` for printing FASTA/Q records in a range (start:end). [#19](https://github.com/shenwei356/seqkit/issues/19). [usage & example](http://bioinf.shenwei.me/seqkit/usage/#range).
    - add new command `concate` for concatenating sequences with same ID from multiple files. [usage & example](http://bioinf.shenwei.me/seqkit/usage/#concate).
- [SeqKit v0.6.0](https://github.com/shenwei356/seqkit/releases/tag/v0.6.0) - 2017-06-21
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.6.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.6.0)
    - add new command `genautocomplete` to generate **shell autocompletion** script! ([#17](https://github.com/shenwei356/seqkit/issues/17))
    - add new command `seqkit dup` for duplicating sequences ([#16](https://github.com/shenwei356/seqkit/issues/16))
    - `seqkit stats -a` does not show L50 which may brings confusion ([#15](https://github.com/shenwei356/seqkit/issues/15))
    - `seqkit subseq --bed`: more robust for bad BED files
- [SeqKit v0.5.5](https://github.com/shenwei356/seqkit/releases/tag/v0.5.5) - 2017-05-10
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.5.5/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.5.5)
    - Increasing speed of reading `.gz` file by utilizing `gzip` (1.3X),
        it would be much faster if you installed `pigz` (2X).
    - ***Fixing colorful output in Windows***
    - `seqkit locate`: ***add flag `--gtf` and `--bed` to output GTF/BED6 format,
        so the result can be used in `seqkit subseq`***.
    - `seqkit subseq`: fix bug of `--bed`, add checking coordinate.
- [SeqKit v0.5.4](https://github.com/shenwei356/seqkit/releases/tag/v0.5.4) - 2017-04-11
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.5.4/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.5.4)
    - `seqkit subseq --gtf`, add flag `--gtf-tag` to set tag that's outputted as sequence comment
    - fix `seqkit split` and `seqkit sample`: forget not to wrap sequence and quality in output for FASTQ format
    - compile with go1.8.1
- [SeqKit v0.5.3](https://github.com/shenwei356/seqkit/releases/tag/v0.5.3) - 2017-04-01
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.5.3/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.5.3)
    -  `seqkit grep`: fix bug when using `seqkit grep -r -f patternfile`:
      all records will be retrived due to failing to discarding the blank pattern (`""`). #11
- [SeqKit v0.5.2](https://github.com/shenwei356/seqkit/releases/tag/v0.5.2) - 2017-03-24
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.5.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.5.2)
    - `seqkit stats -a` and `seqkit seq -g -G`: change default gap letters from '- ' to '- .'
    - `seqkit subseq`: fix bug of range overflow when using `-d/--down-stream`
        or `-u/--up-stream` for retieving subseq using BED (`--beb`) or GTF (`--gtf`) file.
    - `seqkit locate`: add flag `-G/--non-greedy`, non-greedy mode,
     faster but may miss motifs overlaping with others.
- [SeqKit v0.5.1](https://github.com/shenwei356/seqkit/releases/tag/v0.5.1) - 2017-03-12
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.5.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.5.1)
    - `seqkit restart`: fix bug of flag parsing
- [SeqKit v0.5.0](https://github.com/shenwei356/seqkit/releases/tag/v0.5.0) - 2017-03-11
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.5.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.5.0)
    - **new command `seqkit restart`, for resetting start position for circular genome**.
    - `seqkit sliding`: add flag `-g/--greedy`, exporting last subsequences even shorter than windows size.
    - `seqkit seq`:
        - **add flag `-m/--min-len` and `-M/--max-len` to filter sequences by length**.
        - rename flag `-G/--gap-letter` to `-G/--gap-letters`.
    - `seqkit stat`:
        - renamed to `seqkit stats`, don't worry, old name is still available as an alias.
        - **add new flag `-a/all`, for all statistics, including `sum_gap`, `N50`, and `L50`**.
- [SeqKit v0.4.5](https://github.com/shenwei356/seqkit/releases/tag/v0.4.5) - 2017-02-26
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.4.5/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.4.5)
    - `seqkit seq`: fix bug of failing to reverse quality of FASTQ sequence
- [SeqKit v0.4.4](https://github.com/shenwei356/seqkit/releases/tag/v0.4.4) - 2017-02-17
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.4.4/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.4.4)
    - `seqkit locate`: fix bug of missing regular-expression motifs containing
     non-DNA characters (e.g., `ACT.{6,7}CGG`) from motif file (`-f`).
    - compiled with go v1.8.
- [SeqKit v0.4.3](https://github.com/shenwei356/seqkit/releases/tag/v0.4.3) - 2016-12-22
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.4.3/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.4.3)
    - fix bug of `seqkit stat`: `min_len` always be `0` in versions: v0.4.0, v0.4.1, v0.4.2
- [SeqKit v0.4.2](https://github.com/shenwei356/seqkit/releases/tag/v0.4.2) - 2016-12-21
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.4.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.4.2)
    - fix header information of `seqkit subseq` when restriving up- and down-steam
sequences using GTF/BED file.
- [SeqKit v0.4.1](https://github.com/shenwei356/seqkit/releases/tag/v0.4.1) - 2016-12-16
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.4.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.4.1)
    - enchancement: remove redudant regions for `seqkit locate`.
- [SeqKit v0.4.0](https://github.com/shenwei356/seqkit/releases/tag/v0.4.0) - 2016-12-07
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.4.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.4.0)
    - fix bug of `seqkit locate`, e.g, only find two locations
(`1-4`, `7-10`, missing `4-7`) of `ACGA` in `ACGACGACGA`.
    - better output of `seqkit stat` for empty file.
- [SeqKit v0.3.9](https://github.com/shenwei356/seqkit/releases/tag/v0.3.9) - 2016-12-04
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.9/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.9)
    - fix bug of region selection for blank sequences. affected commands include
`seqkit subseq --region`, `seqkit grep --region`, `seqkit split --by-region`.
    - compile with go1.8beta1.
- [SeqKit v0.3.8.1](https://github.com/shenwei356/seqkit/releases/tag/v0.3.8.1) - 2016-11-25
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.8.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.8.1)
    - enhancement and bugfix of `seqkit common`: two or more same files allowed,
fix log information of number of extracted sequences in the first file.
- [SeqKit v0.3.8](https://github.com/shenwei356/seqkit/releases/tag/v0.3.8) - 2016-12-24
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.8/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.8)
    - enhancement of `seqkit common`: better handling of files containing replicated sequences
- [SeqKit v0.3.7](https://github.com/shenwei356/seqkit/releases/tag/v0.3.7) - 2016-12-23
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.7/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.7)
    - fix bug in `seqkit split --by-id` when sequence ID contains invalid characters for system path.
    - add more flags validation for `seqkit replace`.
    - enhancement: raise error when key pattern matches multiple targes in cases of replacing with key-value files and more controls are added.
    - changes: do not wrap sequence and quality in output for FASTQ  format.
- [SeqKit v0.3.6](https://github.com/shenwei356/seqkit/releases/tag/v0.3.6) - 2016-11-03
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.6/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.6)
    - add new feature for `seqkit grep`: new flag `-R` (`--region`) for specifying sequence region for searching.
- [SeqKit v0.3.5](https://github.com/shenwei356/seqkit/releases/tag/v0.3.5) - 2016-10-30
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.5/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.5)
    - fig bug of `seqkit grep`: flag `-i` (`--ignore-case`) did not work when not using regular expression
- [SeqKit v0.3.4.1](https://github.com/shenwei356/seqkit/releases/tag/v0.3.4.1) - 2016-09-21
[![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.4.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.4.1)
    - improve performance of reading (~10%) and writing (100%) gzip-compressed file
    by using `github.com/klauspost/pgzip` package
    - add citation
- [SeqKit v0.3.4](https://github.com/shenwei356/seqkit/releases/tag/v0.3.4) - 2016-09-17
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.4/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.4)
    - bugfix: `seq` wrongly handles only the first one sequence file when multiple files given
    - new feature: `fx2tab` can output alphabet letters of a sequence by flag `-a` (`--alphabet`)
    - new feature: new flag `-K` (`--keep-key`) for `replace`,  when replacing
    with key-value file, one can choose keeping the key as value or not.
- [SeqKit v0.3.3](https://github.com/shenwei356/seqkit/releases/tag/v0.3.3) - 2016-08-18
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.3/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.3)
    - fix bug of `seqkit replace`, wrongly starting from 2 when using `{nr}`
      in `-r` (`--replacement`)
    - new feature: `seqkit replace` supports replacement symbols `{nr}` (record number)
      and `{kv}` (corresponding value of the key ($1) by key-value file)
- [SeqKit v0.3.2](https://github.com/shenwei356/seqkit/releases/tag/v0.3.2) - 2016-08-13
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.2)
    - fix bug of `seqkit split`, error when target file is in a directory.
    - improve performance of `seqkit spliding` for big sequences, and output
      last part even if it's shorter than window sze,
      output of FASTQ is also supported.
- [SeqKit v0.3.1.1](https://github.com/shenwei356/seqkit/releases/tag/v0.3.1.1) - 2016-08-07
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.1.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.1.1)
    - compile with go1.7rc5, with ***higher performance and smaller size of binary file***
- [SeqKit v0.3.1](https://github.com/shenwei356/seqkit/releases/tag/v0.3.1) - 2016-08-02
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.1)
    - improve speed of `seqkit locate`
- [SeqKit v0.3.0](https://github.com/shenwei356/seqkit/releases/tag/v0.3.0) - 2016-07-28
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.3.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.3.0)
    - use fork of github.com/brentp/xopen, using `zcat` for speedup of .gz file
      reading on \*nix systems.
    - improve speed of parsing sequence ID when creating FASTA index
    - reduce memory usage of `seqkit subseq --gtf`
    - fix bug of `seqkit subseq` when using flag `--id-ncbi`
    - fix bug of `seqkit split`, outdir error
    - fix bug of `seqkit seq -p`, last base is wrongly failed to convert when
      sequence length is odd.
    - add "sum_len" result for output of `seqkit stat`
- [seqkit v0.2.9](https://github.com/shenwei356/seqkit/releases/tag/v0.2.9) - 2016-07-24
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.9/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.9)
    - fix minor bug of `seqkit split` and `seqkit shuffle`,
      header name error due to improper use of pointer
    - add option `-O (--out-dir)` to `seqkit split`
- [seqkit v0.2.8](https://github.com/shenwei356/seqkit/releases/tag/v0.2.8) - 2016-07-19
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.8/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.8)
    - improve speed of parsing sequence ID, not using regular expression for default `--id-regexp`
    - improve speed of record outputing for small-size sequences
    - fix minor bug: `seqkit seq` for blank record
    - update benchmark result
- [seqkit v0.2.7](https://github.com/shenwei356/seqkit/releases/tag/v0.2.7) - 2016-07-18
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.7/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.7)
    - ***reduce memory usage*** by optimize the outputing of sequences.
      detail: using [`BufferedByteSliceWrapper`](https://godoc.org/github.com/shenwei356/util/byteutil#BufferedByteSliceWrapper) to resuse bytes.Buffer.
    - ***reduce memory usage and improve speed*** by using custom buffered
     reading mechanism, instead of using standard library `bufio`,
      which is slow for large genome sequence.
    - discard strategy of "buffer" and "chunk" of FASTA/Q records,
      just parse records one by one.
    - delete global flags `-c (--chunk-size)` and `-b (--buffer-size)`.
    - add function testing scripts
- [seqkit v0.2.6](https://github.com/shenwei356/seqkit/releases/tag/v0.2.6) - 2016-07-01
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.6/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.6)
    - fix bug of `seqkit subseq`: Inplace subseq method leaded to wrong result
- [seqkit v0.2.5.1](https://github.com/shenwei356/seqkit/releases/tag/v0.2.5.1)
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.5.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.5.1)
    - fix a bug of `seqkit subseq`: chromesome name was not be converting to lower case when using `--gtf` or `--bed`
- [seqkit v0.2.5](https://github.com/shenwei356/seqkit/releases/tag/v0.2.5) - 2016-07-01
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.5/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.5)
    - fix a serious bug brought in `v0.2.3`, using unsafe method to convert `string` to `[]byte`
    - add awk-like built-in variable of record number (`{NR}`) for `seqkit replace`
- [seqkit v0.2.4.1](https://github.com/shenwei356/seqkit/releases/tag/v0.2.4.1) - 2016-06-12
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.4.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.4.1)
    - fix several bugs from library `bio`, affected situations:
        - Locating patterns in sequences by pattern FASTA file: `seqkit locate -f`
        - Reading FASTQ file with record of which the quality starts with `+`
    - add command `version`
- [seqkit v0.2.4](https://github.com/shenwei356/seqkit/releases/tag/v0.2.4) - 2016-05-31
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.4/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.4)
    - add subcommand `head`
- [seqkit v0.2.3](https://github.com/shenwei356/seqkit/releases/tag/v0.2.3) - 2016-05-08
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.3/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.3)
    - reduce memory occupation by avoid copy data when convert `string` to `[]byte`
    - speedup reverse-complement by avoid repeatly calling functions
- [seqkit v0.2.2](https://github.com/shenwei356/seqkit/releases/tag/v0.2.2) - 2016-05-06
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.2)
    - reduce memory occupation of subcommands that use FASTA index
- [seqkit v0.2.1](https://github.com/shenwei356/seqkit/releases/tag/v0.2.1) - 2016-05-02
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.1)
    - improve performance of outputing.
    - fix bug of `seqkit seq -g` for FASTA fromat
    - some other minor fix of code and docs
    - update benchmark results
- [seqkit v0.2.0](https://github.com/shenwei356/seqkit/releases/tag/v0.2.0) - 2016-04-29
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.2.0/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.2.0)
    - ***reduce memory usage of writing output***
    - fix bug of `subseq`, `shuffle`, `sort` when reading from stdin
    - reduce memory usage of `faidx`
    - make validating sequences an optional option in `seq` command, it saves some time.
- [seqkit v0.1.9](https://github.com/shenwei356/seqkit/releases/tag/v0.1.9) - 2016-04-26
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.9/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.9)
    - using custom FASTA index file extension: `.seqkit.fai`
    - reducing memory usage of `sample --number --two-pass`
    - ***change default CPU number to 2 for multi-cpus computer, and 1 for single-CPU computer***
- [seqkit v0.1.8](https://github.com/shenwei356/seqkit/releases/tag/v0.1.8) - 2016-04-24
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.8/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.8)
    - add subcommand `rename` to rename duplicated IDs
    - add subcommand `faidx` to create FASTA index file
    - ***utilize faidx to improve performance of `subseq`***
    - *`shuffle`, `sort` and split support two-pass mode (by flag `-2`) with faidx to reduce memory usage.*
    - document update
- [seqkit v0.1.7](https://github.com/shenwei356/seqkit/releases/tag/v0.1.7) - 2016-04-21
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.7/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.7)
    - ***add support for (multi-line) FASTQ format***
    - update document, add technical details
    - rename subcommands `fa2tab` and `tab2fa` to `fx2tab` and `tab2fx`
    - add subcommand `fq2fa`
    - add column "seq_format" to `stat`
    - add global flag `-b` (`--bufer-size`)
    - little change of flag in `subseq` and some other commands
- [seqkit v0.1.6](https://github.com/shenwei356/seqkit/releases/tag/v0.1.6) - 2016-04-07
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.6/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.6)
    - add subcommand `replace`
- [seqkit v0.1.5.2](https://github.com/shenwei356/seqkit/releases/tag/v0.1.5.2) - 2016-04-06
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.5.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.5.2)
    - fix bug of `grep`, when not using flag `-r`, flag `-i` will not take effect.
- [seqkit v0.1.5.1](https://github.com/shenwei356/seqkit/releases/tag/v0.1.5.1)
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.5.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.5.1)
    - fix result of `seqkit sample -n`
    - fix benchmark script
- [seqkit v0.1.5](https://github.com/shenwei356/seqkit/releases/tag/v0.1.5) - 2016-03-29
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.5/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.5)
    - add global flag `--id-ncbi`
    - add flag `-d` (`--dup-seqs-file`) and `-D` (`--dup-num-file`) for subcommand `rmdup`
    - make using MD5 as an optional flag `-m` (`--md5`) in subcommand `rmdup` and `common`
    - fix file name suffix of `seqkit split` result
    - minor modification of `sliding` output
- [seqkit v0.1.4.1](https://github.com/shenwei356/seqkit/releases/tag/v0.1.4.1) - 2016-03-27
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.4.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.4.1)
    - change alignment of `stat` output
    - preciser CPUs number control
- [seqkit v0.1.4](https://github.com/shenwei356/seqkit/releases/tag/v0.1.4) - 2016-03-25
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.4/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.4)
    - add subcommand `sort`
    - improve subcommand `subseq`: supporting of getting subsequences by GTF and BED files
    - change name format of `sliding` result
    - prettier output of `stat`
- [seqkit v0.1.3.1](https://github.com/shenwei356/seqkit/releases/tag/v0.1.3.1) - 2016-03-16
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.3.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.3.1)
    - Performance improvement by reducing time of cleaning spaces
    - Document update
- [seqkit v0.1.3](https://github.com/shenwei356/seqkit/releases/tag/v0.1.3) - 2016-03-15
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.3/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.3)
    - **Further performance improvement**
    - Rename sub command `extract` to `grep`
    - Change default value of flag `--threads` back CPU number of current device,
      change default value of flag `--chunk-size` back 10000 sequences.
    - Update benchmark
- [seqkit v0.1.2](https://github.com/shenwei356/seqkit/releases/tag/v0.1.2) - 2016-03-14
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.2/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1.2)
    - Add flag `--dna2rna` and `--rna2dna` to subcommand `seq`.
- [seqkit v0.1.1](https://github.com/shenwei356/seqkit/releases/tag/v0.1.1) - 2016-03-13
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1.1/total.svg)](https://github.com/shenwei356/seqkit/releases/download/v0.1.1)
    - **5.5X speedup of FASTA file parsing** by avoid using regular expression to remove spaces ([detail](https://github.com/shenwei356/bio/commit/2457b877cf1b8d79d05adb1a8952f2dff9046eaf) ) and using slice indexing instead of map to validate letters ([detail](https://github.com/shenwei356/bio/commit/0f5912f6a3c6d737faacf9212f62d11c94e5044a))
    - Change default value of global flag `-- thread` to 1. Since most of the subcommands are I/O intensive,  For computation intensive jobs, like extract and locate, you may set a bigger value.
    - Change default value of global flag `--chunk-size` to 100.
    - Add subcommand `stat`
    - Fix bug of failing to automatically detect alphabet when only one record in file.
- [seqkit v0.1](https://github.com/shenwei356/seqkit/releases/tag/v0.1) - 2016-03-11
  [![Github Releases (by Release)](https://img.shields.io/github/downloads/shenwei356/seqkit/v0.1/total.svg)](https://github.com/shenwei356/seqkit/releases/tag/v0.1)
    - first release of seqkit