README.md

line-replace

Replace a line in a file with passed string.

Install

Global, for command line usage: npm i -g line-replace

Local, for programatic usage in your project: npm i line-replace

Command line usage

    USAGE:
      line-replace [file]:[line] [[string]]

    EXAMPLE:
      line-replace sample.txt:7 'New content for line seven.'


    Passed string will replace passed line number on passed file.
    If string is not provided, the line will be cleared.

You can also use it directly with npx:

npx line-replace [file]:[line] [[string]]

For example:

npx line-replace test.txt:1 'HEY!'

Note that line numbers start at 1.

Programatic usage

const lineReplace = require('line-replace')
lineReplace({
  file: 'a-file.txt',
  line: 42,
  text: 'Answer to the Ultimate Question of Life, the Universe, and Everything.',
  addNewLine: true,
  callback: ({ file, line, text, replacedText, error }) => {}
})

addNewLine defaults to true, which doesn't add or remove lines from the original document.

Setting it to false is the equivalent of removing the passed line and appending the passed text to the next line.

For example, with the following content:

First line.
Second line.
Third line.

Running:

lineReplace({
  file: 'the-file.txt',
  line: 2,
  text: 'LOOK: ',
  addNewLine: false,
  callback: ({file, line, text, replacedText, error}) => {}
})

Will result in:

First line.
LOOK: Third line.

Should it work with big files?

Yeah. line-replace uses read and write streams, so it should work ok with big files.

Changelog

v2.0

• FS sync methods replaced with async + utils.promisify (added in Node v8).
• Passing errors to callback.