kubun

README

Kubun くぶん

A CLI for slicing and indexing delimiter-separated text

Kubun draws inspiration from Python's simple yet powerful slice syntax. My aim is for it to be a more intuitive solution for slicing fields and segments of text on the command line than tools like cut, awk, and sed.

Install

go install github.com/alexandersisco/kubun@latest

Usage

Kubun takes up to two positional arguments: the SLICE pattern followed by the optional INPUT.

Python-like syntax:

The syntax for Kubun's slice pattern follows that of Python which includes the following components [start:stop:step]. Each is a zero-based index into the delimited fields being sliced. The stop index is exclusive, meaning Kubun will stop before the field that the index points to, excluding it from the output. A negative start or stop index is measured from the end of the input with a -1 representing the last field. For brevity, the step may be omitted: like this: [start:stop].

Here are some basic examples:

kubun '[:]' /usr/bin/sort             # -> /usr/bin/sort
kubun '[:-1]' /usr/bin/sort           # -> /usr/bin
kubun '[-1:]' /usr/bin/sort           # -> sort
kubun '[-2:]' /usr/bin/sort           # -> bin/sort

Select a single field by placing the field's index between the brackets. Here are some examples:

kubun '[0]' /usr/bin/sort             # -> '' (Blank since there is nothing before the first delimiter)
kubun '[1]' /usr/bin/sort             # -> usr
kubun '[-1]' /usr/bin/sort            # -> sort

You can also pipe text into Kubun:

echo "/usr/bin/sort" | kubun '[-3:]'  # -> usr/bin/sort

Kubun supports reversing fields by passing in a negative step. Indexing and slicing in reverse work the same way as they do in Python, meaning, that a reverse slice walks backward through the fields from right to left. So remember, your start index must be greater than your stop index and the field pointed to by your stop index is not included in the resulting slice.

kubun '[::-1]' /usr/bin/sort          # -> sort/bin/usr/
kubun '[2:0:-1]' /usr/bin/sort        # -> bin/usr
kubun '[:0:-1]' /usr/bin/sort         # -> sort/bin/usr

Delimiters

By default, Kubun looks for the "/" forward slash delimiter. To slice based on a different delimiter, place the delimiter that you want to use immediately before the slice pattern as in the following example:

kubun ':[0:2]' $PATH                  # -> /bin:/usr/bin

Kubun makes it easy to replace delimiters.

To replace the delimiters in a string of text, include the old and new delimiters on either side of the slice pattern like so: '<old>[:]<new>'.

kubun '/[:]\' /usr/bin/sort           # -> \usr\bin\sort
kubun '/[1:], ' /usr/bin/sort         # -> usr, bin, sort
kubun ':[:]\n' $PATH                  # -> /bin
                                      #    /usr/local/bin
                                      #    /usr/bin
                                      #    ...