linsel 0.1.0-alpha.1

A small program to print out selected lines of a file
Documentation 
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# linsel

> **lin**e **sel**ector

A small program that prints out selected lines from its input.

## Installation

Install in the standard way for Rust programs:

```shell
cargo install --bins linsel
```

## Usage

`linsel` takes any number of arguments of the form `<start>-<end>/<step>`, which
means "print out every `<step>`th line from `<start>` to `<end>`, inclusive".
The hyphen can also be replaced with a colon: `<start>:<end>/<step>`.

Line numbers are 1-based: the first line of input is numbered 1, not 0. Any line
selected by any of the arguments will be printed, but each line is only printed
once.

```console
$ seq 20 | linsel 4-10/2 8-17/3
4
6
8
10
11
14
17
```

There are various abbreviated forms:

- If `<start>` is omitted, printing begins with the first line of input.
- If `<end>` is omitted, printing extends all the way to the last line of input.
- If `/<step>` is omitted, the step defaults to 1.
- A single number `<n>` means exactly line `<n>`, equivalent to `<n>-<n>/1`.

```console
$ seq 10 | linsel -2
1
2
$ seq 10 | linsel 9-
9
10
$ seq 10 | linsel 4
4
```

### Recipes

- `head -n <NUM>` is equivalent to `linsel -<NUM>`
- `head -n -<NUM>` is equivalent to `linsel <NUM>-`

## Why "linsel"?

Plus the name rhymes with "tinsel" and I think that's kind of cute. But really,
it's mostly because naming is hard, this one was unclaimed, and I didn't come up
with anything better in a few days.