🪓
hck
A sharp cut(1) clone.
hck is a shortening of hack, a rougher form of cut.
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 of hck on its own makes it stand out over awk, cut, xsv or other such tools. Where hck 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.
Features
- Reordering of output columns! i.e. if you use
-f4,2,8the output columns will appear in the order4,2,8 - Delimiter treated as a regex (with
-R), i.e. you can split on multiple spaces without and extra pipe totr! - Specification of output delimiter
- Selection of columns by header string literal with the
-Foption, or by regex by setting the-rflag - Input files will be automatically decompressed if their file extension is recognizable and a local binary exists to perform the decompression (similar to ripgrep). See Decompression.
- Speed
Non-goals
hckdoes not aim to be a complete CSV / TSV parser a laxsvwhich will respect quoting rules. It acts similar tocutin 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.
hckwill always be a line-by-line tool where newlines are the standard\n\r\n.
Install
- Homebrew / Linuxbrew
brew tap sstadick/hck
brew install hck
* Built with profile guided optimizations
- MacPorts
sudo port selfupdate
sudo port install hck
- Debian (Ubuntu)
curl -LO https://github.com/sstadick/hck/releases/download/<latest>/hck-linux-amd64.deb
sudo 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 the releases 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 issue
rustup component add llvm-tools-preview
git clone https://github.com/sstadick/hck
cd hck
bash pgo_local.sh
cp ./target/release/hck ~/.cargo/bin/hck
- 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.
Examples
Splitting with a string literal
❯ 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">>
Splitting with a regex delimiter
# note, '\s+' is the default
❯ ps aux | hck -f1-3,5- | head -n4
USER PID %CPU VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 169452 13472 ? Ss Jun21 0:19 /sbin/init splash
root 2 0.0 0 0 ? S Jun21 0:00 [kthreadd]
root 3 0.0 0 0 ? I< Jun21 0:00 [rcu_gp]
Reordering output columns
❯ ps aux | hck -f2,1,3- | head -n4
PID USER %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
1 root 0.0 0.0 169452 13472 ? Ss Jun21 0:19 /sbin/init splash
2 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]
Changing the output record separator
❯ ps aux | hck -D'___' -f2,1,3 | head -n4
PID___USER___%CPU
1___root___0.0
2___root___0.0
3___root___0.0
Select columns with regex
# Note the order match the order of the -F args
ps aux | hck -r -F '^ST.*' -F '^USER$' | head -n4
STAT START USER
Ss Jun21 root
S Jun21 root
I< Jun21 root
Automagic decompresion
❯ gzip ./README.md
❯ hck -Ld' ' -f1-3,5- -z ./README.md.gz | head -n4
# 🪓 hck
<p align="center">
<a src="https://github.com/sstadick/hck/workflows/Check/badge.svg" alt="Build Status">>
Splitting on multiple characters
# with string literal
❯ printf 'this$;$is$;$a$;$test\na$;$b$;$3$;$four\n' > test.txt
❯ hck -Ld'$;$' -f3,4 ./test.txt
a test
3 four
# with an interesting regex
❯ printf 'this123__is456--a789-test\na129_-b849-_3109_-four\n' > test.txt
❯ hck -d'\d{3}[-_]+' -f3,4 ./test.txt
a test
3 four
Benchmarks
This set of benchmarks is simply meant to show that hck 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 for gcut, for example, we use tr to convert the space runs to a single space and then pipe to gcut.
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.
Hardware
Ubuntu 20 AMD Ryzen 9 3950X 16-Core Processor w/ 64 GB DDR4 memory and 1TB NVMe Drive
Data
The all_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.
Tools
cut:
mawk:
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)
Single character delimiter benchmark
| Command | Mean [s] | Min [s] | Max [s] | Relative |
|---|---|---|---|---|
hck -Ld, -f1,8,19 ./hyper_data.txt > /dev/null |
1.387 ± 0.019 | 1.369 | 1.407 | 1.00 |
hck -Ld, -f1,8,19 --no-mmap ./hyper_data.txt > /dev/null |
1.549 ± 0.002 | 1.547 | 1.552 | 1.12 ± 0.02 |
hck -d, -f1,8,19 ./hyper_data.txt > /dev/null |
1.437 ± 0.001 | 1.436 | 1.438 | 1.04 ± 0.01 |
hck -d, -f1,8,19 --no-mmap ./hyper_data.txt > /dev/null |
1.706 ± 0.017 | 1.694 | 1.735 | 1.23 ± 0.02 |
choose -f , -i ./hyper_data.txt 0 7 18 > /dev/null |
4.333 ± 0.063 | 4.254 | 4.384 | 3.12 ± 0.06 |
tsv-select -d, -f 1,8,19 ./hyper_data.txt > /dev/null |
1.708 ± 0.002 | 1.705 | 1.712 | 1.23 ± 0.02 |
xsv select -d, 1,8,19 ./hyper_data.txt > /dev/null |
5.600 ± 0.010 | 5.589 | 5.615 | 4.04 ± 0.06 |
awk -F, '{print $1, $8, $19}' ./hyper_data.txt > /dev/null |
4.933 ± 0.059 | 4.901 | 5.038 | 3.56 ± 0.06 |
cut -d, -f1,8,19 ./hyper_data.txt > /dev/null |
7.421 ± 1.302 | 6.797 | 9.749 | 5.35 ± 0.94 |
Multi-character delimiter benchmark
| Command | Mean [s] | Min [s] | Max [s] | Relative |
|---|---|---|---|---|
hck -Ld' ' -f1,8,19 ./hyper_data_multichar.txt > /dev/null (note, that's three spaces) |
1.827 ± 0.009 | 1.818 | 1.842 | 1.00 |
hck -Ld' ' -f1,8,19 --no-mmap ./hyper_data_multichar.txt > /dev/null (note, that's three spaces) |
2.123 ± 0.013 | 2.105 | 2.133 | 1.16 ± 0.01 |
hck -d'[[:space:]]+' -f1,8,19 ./hyper_data_multichar.txt > /dev/null |
9.366 ± 0.202 | 9.009 | 9.506 | 5.13 ± 0.11 |
hck -d'[[:space:]]+' --no-mmap -f1,8,19 ./hyper_data_multichar.txt > /dev/null |
9.636 ± 0.030 | 9.588 | 9.666 | 5.27 ± 0.03 |
hck -d'\s+' -f1,8,19 ./hyper_data_multichar.txt > /dev/null |
10.038 ± 0.005 | 10.036 | 10.047 | 5.49 ± 0.03 |
hck -d'\s+' -f1,8,19 --no-mmap ./hyper_data_multichar.txt > /dev/null |
9.913 ± 0.113 | 9.725 | 9.997 | 5.43 ± 0.07 |
choose -f ' ' -i ./hyper_data_multichar.txt 0 7 18 > /dev/null |
6.600 ± 0.071 | 6.555 | 6.723 | 3.61 ± 0.04 |
choose -f '[[:space:]]' -i ./hyper_data_multichar.txt 0 7 18 > /dev/null |
10.764 ± 0.041 | 10.703 | 10.809 | 5.89 ± 0.04 |
choose -f '\s' -i ./hyper_data_multichar.txt 0 7 18 > /dev/null |
36.866 ± 0.144 | 36.682 | 37.076 | 20.18 ± 0.13 |
awk -F' ' '{print $1, $8 $19}' ./hyper_data_multichar.txt > /dev/null |
6.602 ± 0.024 | 6.568 | 6.631 | 3.61 ± 0.02 |
awk -F' ' '{print $1, $8, $19}' ./hyper_data_multichar.txt > /dev/null |
5.894 ± 0.052 | 5.850 | 5.983 | 3.23 ± 0.03 |
awk -F'[:space:]+' '{print $1, $8, $19}' ./hyper_data_multichar.txt > /dev/null |
10.962 ± 0.190 | 10.733 | 11.145 | 6.00 ± 0.11 |
< ./hyper_data_multichar.txt tr -s ' ' | cut -d ' ' -f1,8,19 > /dev/null |
7.604 ± 0.096 | 7.521 | 7.730 | 4.16 ± 0.06 |
< ./hyper_data_multichar.txt tr -s ' ' | tail -n+2 | xsv select -d ' ' 1,8,19 --no-headers > /dev/null |
6.757 ± 0.191 | 6.447 | 6.943 | 3.70 ± 0.11 |
< ./hyper_data_multichar.txt tr -s ' ' | hck -Ld' ' -f1,8,19 > /dev/null |
6.313 ± 0.040 | 6.269 | 6.365 | 3.45 ± 0.03 |
< ./hyper_data_multichar.txt tr -s ' ' | tsv-select -d ' ' -f 1,8,19 > /dev/null |
6.278 ± 0.036 | 6.238 | 6.328 | 3.44 ± 0.03 |
Decompression
The following table indicates the file extension / binary pairs that are used to try to decompress a file when the -z option is specified:
| Extension | Binary | Type |
|---|---|---|
*.gz |
gzip -d -c |
gzip |
*.tgz |
gzip -d -c |
gzip |
*.bz2 |
bzip2 -d -c |
bzip2 |
*.tbz2 |
bzip -d -c |
gzip |
*.xz |
xz -d -c |
xz |
*.txz |
xz -d -c |
xz |
*.lz4 |
lz4 -d -c |
lz4 |
*.lzma |
xz --format=lzma -d -c |
lzma |
*.br |
brotli -d -c |
brotli |
*.zst |
zstd -d -c |
zstd |
*.zstd |
zstd -q -d -c |
zstd |
*.Z |
uncompress -c |
uncompress |
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 then hck will try to read the compressed file as is. See grep_cli for source code. The end goal is to add a similar preprocessor as ripgrep.
Profile Guided Optimization
See the pgo*.sh scripts for how to build this with optimizations. You will need to install the llvm tools via rustup 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.
TODO
- Add complement argument
- 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 of
hck) - Move tests from main to core
- Add more tests all around
- Add pigz support
- Add a greedy/non-greedy option that will ignore blank fields
split.filter(|s| !s.is_empty() || config.opt.non_greedy) - Experiment with parallel parser as described here This should be very doable given we don't care about escaping quotes and such.
More packages and builds
https://github.com/sharkdp/bat/blob/master/.github/workflows/CICD.yml
![[feature request] select rightmost/trailing indices](https://avatars.githubusercontent.com/u/1513265?v=4)
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