https://github.com/learnbyexample/regexp-cut
Use awk to provide cut like syntax for field extraction
https://github.com/learnbyexample/regexp-cut
awk command-line cut regex
Last synced: 8 months ago
JSON representation
Use awk to provide cut like syntax for field extraction
- Host: GitHub
- URL: https://github.com/learnbyexample/regexp-cut
- Owner: learnbyexample
- License: mit
- Created: 2021-06-18T14:52:12.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2021-07-08T08:48:10.000Z (over 4 years ago)
- Last Synced: 2025-04-09T13:46:58.324Z (9 months ago)
- Topics: awk, command-line, cut, regex
- Language: Shell
- Homepage:
- Size: 21.5 KB
- Stars: 16
- Watchers: 2
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# regexp-cut
Uses `awk` to provide `cut` like syntax for field extraction. The command name is `rcut`.
:warning: :warning: Work under construction!
## Motivation
`cut`'s syntax is handy for many field extraction problems. But it doesn't allow multi-character or regexp delimiters. So, this project aims to provide `cut` like syntax for those cases. Currently uses `mawk` in a `bash` script.
:information_source: **Note** that `rcut` isn't feature compatible or a replacement for the `cut` command. `rcut` helps when you need features like regexp field separator.
## Features
* Default field separation is same as `awk`
* Both input (`-d`) and output (`-o`) field separators can be multiple characters
* Input field separator can use regular expressions
* this script uses `mawk` by default
* you can change it to `gawk` for better regexp support with `-g` option
* If input field separator is a single character, output field separator will also be this same character
* Fixed string input field separator can be enabled by using the `-F` option
* if `-o` is *not* used, value passed to the `-d` option will be set as the output field separator
* Field range can be specified by using `-` separator (same as `cut`)
* `-` by itself means all the fields (this is also the default if `-f` option isn't used at all)
* if start of the range isn't given, default is `1`
* if end of the range isn't given, default is last field of a line
* Negative indexing is allowed if you use `-n` option
* `-1` means the last field, `-2` means the second-last field and so on
* you'll have to use `:` to specify field ranges
* Multiple fields and ranges can be separated using `,` character (same as `cut`)
* Unlike `cut`, order matters with the `-f` option and field/range duplication is also allowed
* this assumes `-c` (complement) is not active
* Using `-c` option will print all the fields in the same order as input except the fields specified by `-f` option
* Using `-s` option will suppress lines not matching the input field separator
* Minimum field number is forced to be `1`
* Maximum field number is forced to be last field of a line
:warning: :warning: Work under construction!
## Examples
```bash
$ cat spaces.txt
1 2 3
x y z
i j k
# by default, it uses awk's space/tab field separation and trimming
# unlike cut, order matters
$ rcut -f3,1 spaces.txt
3 1
z x
k i
# multi-character delimiter
$ echo 'apple:-:fig:-:guava' | rcut -d:-: -f2
fig
# regexp delimiter
$ echo 'Sample123string42with777numbers' | rcut -d'[0-9]+' -f1,4
Sample numbers
# fixed string delimiter
$ echo '123)(%)*#^&(*@#.[](\\){1}\xyz' | rcut -Fd')(%)*#^&(*@#.[](\\){1}\' -f1,2 -o,
123,xyz
# multiple ranges can be specified, order matters
$ printf '1 2 3 4 5\na b c d e\n' | rcut -f2-3,5,1,2-4
2 3 5 1 2 3 4
b c e a b c d
# last field
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -nf-1
cat
5
# except last two fields
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -cnf-2:
apple
1 2 3
# suppress lines without input field delimiter
$ printf '1,2,3,4\nhello\na,b,c\n' | rcut -sd, -f2
2
b
# -g option will switch to gawk
$ echo '1aa2aa3' | rcut -gd'a{2}' -f2
2
```
See [Examples.md](examples/Examples.md) for many more examples.
## Tests
You can use [script.awk](examples/script.awk) to check if all the example code snippets are working as expected.
```bash
$ cd examples/
$ awk -f script.awk Examples.md
```
## TODO
* Step value other than `1` for field range
* What to do if start of the range is greater than end?
* And possibly more...
## Similar tools
* [hck](https://github.com/sstadick/hck) — close to drop in replacement for `cut` that can use a regex delimiter, works on compressed files, etc
* [choose](https://github.com/theryangeary/choose) — negative indexing, regexp based delimiters, etc
## Contributing
* Please open an issue for typos/bugs/suggestions/etc
* **Even for pull requests, open an issue for discussion before submitting PRs**
* In case you need to reach me, mail me at `echo 'bGVhcm5ieWV4YW1wbGUubmV0QGdtYWlsLmNvbQo=' | base64 --decode` or send a DM via [twitter](https://twitter.com/learn_byexample)
## License
This project is licensed under MIT, see [LICENSE](./LICENSE) file for details.