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Read a Text Stream Line by Line with lazylines for Node.js

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Read a Text Stream Line by Line with lazylines for Node.js

· Web Dev Zone
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The new Node.js module “lazylines” allows you to read a text stream, one line at a time, lazily.

 

Examples

The following code reads input from stdin and prepends a number to each line.

    var ll = require("lazylines.js");

    process.stdin.resume();
    var inp = new ll.LineReadStream(process.stdin);
    var count = 1;
    inp.on("line", function (line) {
        console.log(count+": "+ll.chomp(line));
        count++;
    });

There are more examples in the demo/ directory. lazylines is very handy for shell programming. For example, you can implement a script that lets you do the following. 

    # List jpg files, oldest first (-t -r), then wrap
    ls -1 -t -r *.jpg | addlinecounts.js 'mv "{line}" {padi}.jpg' | bash

The above executes commands such as 

    mv "new.jpg" 001.jpg
    mv "newer.jpg" 002.jpg
    mv "newest.jpg" 003.jpg

Installation

    npm install lazylines

Related post

 

Deploying code to production can be filled with uncertainty. Reduce the risks, and deploy earlier and more often. Download this free guide to learn more. Brought to you in partnership with Rollbar.

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Published at DZone with permission of Axel Rauschmayer, DZone MVB. See the original article here.

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