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A sharpcut(1) clone.

hck is a shortening ofhack, a rougher form ofcut.

A close to drop in replacement for cut that can use a regex delimiter instead of a fixed string.Additionally this tool allows for specification of the order of the output columns using the same column selection syntax as cut (see below for examples).

No single feature ofhck on its own makes it stand out overawk,cut,xsv or other such tools. Wherehck excels is making common things easy, such as reordering output fields, or splitting records on a weird delimiter.It is meant to be simple and easy to use while exploring datasets.Think of this as filling a gap betweencut andawk.

hck is dual-licensed under MIT or theUNLICENSE.

• Reordering of output columns! i.e. if you use-f4,2,8 the output columns will appear in the order4,2,8
• Delimiter treated as a regex, i.e. you can split on multiple spaces without an extra pipe totr!
• Specification of output delimiter
• Selection of columns by header string literal with the-F option, or by regex by setting the-r flag
• Input files will be automatically decompressed if their file extension is recognizable and a local binary exists to perform the decompression (similar to ripgrep). SeeDecompression.
• Output can be gzip compressed using the multi-threaded compressors fromgzp with-Z flag
  • This gzipped output is in BGZF format and can be indexed and queried withtabix
• Exclude fields by index or by header.
• Speed

• hck does not aim to be a complete CSV / TSV parser a laxsv which will respect quoting rules. It acts similar tocut in that it will split on the delimiter no matter where in the line it is.
• Delimiters cannot contain newlines... well they can, they will just never be seen.hck will always be a line-by-line tool where newlines are the standard\n\r\n.

• Homebrew / Linuxbrew

brew tap sstadick/hckbrew install hck

• Conda

# Note, this version lags by about a dayconda install -c conda-forge hck

• MacPorts

# Note, version may lag behind latestsudo port selfupdatesudo port install hck

• Debian (Ubuntu)

curl -LO https://github.com/sstadick/hck/releases/download/<latest>/hck-linux-amd64.debsudo dpkg -i hck-linux-amd64.deb

* Built with profile guided optimizations

• With the Rust toolchain:

export RUSTFLAGS='-C target-cpu=native'cargo install hck

• From thereleases page (the binaries have been built with profile guided optimizations)

• Or, if you want the absolute fastest possible build that makes use of profile guided optimizations AND native cpu features:

# Assumes you are on stable rust# NOTE: this won't work on windows, see CI for linked issuecargo install justgit clone https://github.com/sstadick/hckcd hckjust install-native

• PRs are both welcome and encouraged for adding more packaging options and build types! I'd especially welcome PRs for the windows family of package managers / general making sure things are windows friendly.

❯ hck -Ld'' -f1-3,5- ./README.md| head -n4#       🪓      hck<p      align="center"><a      src="https://github.com/sstadick/hck/workflows/Check/badge.svg" alt="Build      Status"></a>

# note, '\s+' is the default❯ ps aux| hck -f1-3,5-| head -n4USER    PID     %CPU    VSZ     RSS     TTY     STAT    START   TIME    COMMANDroot    1       0.0     169452  13472?       Ss      Jun21   0:19    /sbin/init      splashroot    2       0.0     0       0?       S       Jun21   0:00    [kthreadd]root    3       0.0     0       0?       I<      Jun21   0:00    [rcu_gp]

❯ ps aux| hck -f2,1,3-| head -n4PID     USER    %CPU    %MEM    VSZ     RSS     TTY     STAT    START   TIME    COMMAND1       root    0.0     0.0     169452  13472?       Ss      Jun21   0:19    /sbin/init      splash2       root    0.0     0.0     0       0?       S       Jun21   0:00    [kthreadd]3       root    0.0     0.0     0       0?       I<      Jun21   0:00    [rcu_gp]

❯ ps aux| hck -e3,5| head -n4USER    PID     %MEM    RSS     TTY     STAT    START   TIME    COMMANDroot    1       0.0     14408?       Ss      Jun21   0:27    /sbin/init      splashroot    2       0.0     0?       S       Jun21   0:01    [kthreadd]root    3       0.0     0?       I<      Jun21   0:00    [rcu_gp]

❯  ps aux| hck -r -E"CPU" -E"^ST.*"| head -n4USER    PID     %MEM    VSZ     RSS     TTY     TIME    COMMANDroot    1       0.0     170224  14408?       0:27    /sbin/init      splashroot    2       0.0     0       0?       0:01    [kthreadd]root    3       0.0     0       0?       0:00    [rcu_gp]

❯ ps aux| hck -D'___' -f2,1,3| head -n4PID___USER___%CPU1___root___0.02___root___0.03___root___0.0

# Note the order match the order of the -F argsps aux| hck -r -F'^ST.*' -F'^USER$'| head -n4STAT    START   USERSs      Jun21   rootS       Jun21   rootI<      Jun21   root

❯ gzip ./README.md❯ hck -Ld'' -f1-3,5- -z ./README.md.gz| head -n4#       🪓      hck<p      align="center"><a      src="https://github.com/sstadick/hck/workflows/Check/badge.svg" alt="Build      Status"></a>

# with string literal❯printf'this$;$is$;$a$;$test\na$;$b$;$3$;$four\n'> test.txt❯ hck -Ld'$;$' -f3,4 ./test.txtatest3       four# with an interesting regex❯printf'this123__is456--a789-test\na129_-b849-_3109_-four\n'> test.txt❯ hck -d'\d{3}[-_]+' -f3,4 ./test.txtatest3       four

This one requires some explaining first. Basically, by-index and by-header selections each have their own "order", and then the orders are merged ex:

❯printf'a,b,c,d,e\n1,2,3,4,5\n'| hck -d, -D: -f3 -F'b' -F'a'b:c:a2:3:1

In the by-index group, we've specified column 3 to be in output position 0. In the by-header group, we've specified that columnb be in position 0. They by-index and by-header selections are merged together and when merging, if there are two outputs specified to be in the same output position the are output in input order (input meaning the order of columns in the input data).

This can lead to unexpected outcomes, such as the following example wherea now comes first in the output when compared to the example above.

❯printf'a,b,c,d,e\n1,2,3,4,5\n'| hck -d, -D: -f3 -F'a'a:c1:3

Takeaway: be careful when a specific output order is desired and you are mixing and matching by-index and by-header field selections.

This set of benchmarks is simply meant to show thathck is in the same ballpark as other tools. These are meant to capture real world usage of the tools, so in the multi-space delimiter benchmark forgcut, for example, we usetr to convert the space runs to a single space and then pipe togcut.

Note this is not meant to be an authoritative set of benchmarks, it is just meant to give a relative sense of performance of different ways of accomplishing the same tasks.

Ubuntu 20 AMD Ryzen 9 3950X 16-Core Processor w/ 64 GB DDR4 memory and 1TB NVMe Drive

Theall_train.csv data is used.

This is a CSV dataset with 7 million lines. We test it both using, as the delimiter, and then also using\s\s\s as a delimiter.

PRs are welcome for benchmarks with more tools, or improved (but still realistic) pipelines for commands.

cut:

• https://www.gnu.org/software/coreutils/manual/html_node/The-cut-command.html
• 8.30

mawk:

• https://invisible-island.net/mawk/mawk.html
• v1.3.4

xsv:

• https://github.com/BurntSushi/xsv
• v0.13.0 (compiled locally with optimizations)

tsv-utils:

• https://github.com/eBay/tsv-utils
• v2.2.0 (ldc2, compiled locally with optimizations)

choose:

• https://github.com/theryangeary/choose
• v1.3.2 (compiled locally with optimizations)

The following table indicates the file extension / binary pairs that are used to try to decompress a file when the-z option is specified:

When a file with one of the extensions above is found,hck will open a subprocess running the the decompression tool listed above and read from the output of that tool. If the binary can't be found thenhck will try to read the compressed file as is. Seegrep_cli for source code. The end goal is to add a similar preprocessor asripgrep. Where there are multiple binaries for a given type, they are tried in the order listed above.

See thepgo*.sh scripts for how to build this with optimizations. You will need to install the llvm tools viarustup component add llvm-tools-preview for this to work. Building with PGO seems to improve performance anywhere from 5-30% depending on the platform and codepath. i.e. on mac os it seems to have a larger effect, and on the regex codepath it also seems to have a greater effect.

• Add output compression detection when writing to a file
• Don't reparse fields / headers for each new file
• Figure out how to better reuse / share a vec
• Support indexing from the end (unlikely though)
• Bake in grep / filtering somehow (this will not be done at the expense of the primary utility ofhck)
• Move tests from main to core
• Add more tests all around
• Experiment with parallel parser as describedhere This should be very doable given we don't care about escaping quotes and such.

https://github.com/sharkdp/bat/blob/master/.github/workflows/CICD.yml

• rust-coreutils-cut
• ripgrep