https://github.com/ushelp/easy-read-last-lines
Read the last N lines in the file. (like tail -n)
https://github.com/ushelp/easy-read-last-lines
Last synced: 11 months ago
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Read the last N lines in the file. (like tail -n)
- Host: GitHub
- URL: https://github.com/ushelp/easy-read-last-lines
- Owner: ushelp
- License: mit
- Created: 2022-05-12T10:15:36.000Z (about 4 years ago)
- Default Branch: main
- Last Pushed: 2023-02-16T14:36:51.000Z (over 3 years ago)
- Last Synced: 2025-06-06T17:52:12.710Z (about 1 year ago)
- Language: JavaScript
- Size: 34.2 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- Funding: .github/FUNDING.yml
- License: LICENSE
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README
# Easy-Read-Last-Lines
High performance read the last N lines in the file or text across platforms. (like tail -n)
## Table of contents
- [Feature](#feature)
- [Installation](#installation)
- [Usage](#usage)
- [Functions](#functions)
- [License](#license)
- [End](#end)
## Feature
- High performance read
- Compatible with newlines on different platforms/format: `\r`, `\n`, `\r\n`
- Support setting character `encoding`
- Support get a `String` or `Buffer` object from file
## Installation
```BASH
npm install easy-read-last-lines
```
## Usage
```JS
const erll = require('easy-read-last-lines');
```
### Read last N lines string from File
```JS
let fielPath='YOUR_FILE_PATH';
// Read last N lines string from File - Asynchronously
erll.readFromFile(filePath, 3).then(function(lines) {
console.log(lines);
}).catch(function(err) {
console.log(err.message);
});
// Read last N lines string from File - Synchronously
let lines = await erll.readFromFile(filePath, 3, 'utf8');
console.log(lines);
// Read an array of last N line string from File
let linesArray = await erll.readArrayFromFile(filePath, 3, 'utf8');
console.log(linesArray);
```
### Read last N lines buffer data from File
```JS
let fielPath='YOUR_FILE_PATH';
// Asynchronously
erll.readBufferFromFile(filePath, 1).then(function(buffer) {
console.log(buffer.toString('base64'));
}).catch(function(err) {
console.log(err.message);
});
// Synchronously
let buffer = await erll.readBufferFromFile(filePath, 1);
console.log(buffer.toString('base64'));
```
### Read last N lines string from Text
```JS
var text = `
Easy
Read
Last
Line`;
var text2 = `Easy\nRead\rLast\r\nLine`
// Read last N lines string from Text
var lines = erll.readFromText(text, 2);
console.log(lines);
// Read an array of last N line string from Text
var linesArray = erll.readArrayFromText(text2, 3);
console.log(linesArray);
```
### Convert multiline text to array of string
```JS
var text = `Easy\nRead\rLast\r\nLine`;
console.log(erll.linesToArray(lines));
```
## Functions
- **readFromFile(filePath, maxLine, [encoding]): Promise**
- `filePath`: file path(direct or relative path to file)
- `maxLine`: max number of last lines to read in
- `encoding`: When converting between Buffers and strings, a character encoding may be specified. If no character encoding is specified, `UTF-8` will be used as the default. [buffers-and-character-encodings](https://nodejs.org/api/buffer.html#buffers-and-character-encodings)
- **readArrayFromFile(filePath, maxLine, [encoding]): Promise**
- `filePath`: file path(direct or relative path to file)
- `maxLine`: max number of last lines to read in
- `encoding`: When converting between Buffers and strings, a character encoding may be specified. If no character encoding is specified, `UTF-8` will be used as the default. [buffers-and-character-encodings](https://nodejs.org/api/buffer.html#buffers-and-character-encodings)
- **readBufferFromFile(filePath, maxLine): Promise**
- `filePath`: file path(direct or relative path to file)
- `maxLine`: max number of last lines to read in
- **readFromText(text, maxLine): String**
- `text`: multiline string
- `maxLine`: max number of last lines to read in
- **readArrayFromText(text, maxLine): String**
- `text`: multiline string
- `maxLine`: max number of last lines to read in
- **linesToArray(text): Array**
- `text`: multiline string
## License
MIT License
## End
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