Changeline NPM

changeline

Search and replace in lines of files across directories.

Changeline is your basic file search and replace. But it goes beyond regular expressions and paths. You must submit a list of files via STDIN, so it is up to you to select a directory scan program. You can use UNIX find with a *.html wildcard for example.

Furthermore, there is no question about matches spanning lines. Changeline simply sees one line at a time. It uses node readline under the hood.

Finally, changeline is a precision device aimed at altering lines of code without the need for AST processing. You can for example target CSS Class Names in .css/.html and .js/es6 files, and it will plow through ES7 and CSS4 and whatever else comes its way.

Installation

changeline is a command line program, and it is installed via npm which comes along with node. Please install node first, and then run npm install -g changeline to get changeline onto your system.

Usage

After installation via npm install -g changeline you should begin by piping in a list of files separated by a new line. Example of making a dynamic list find . -name example.html -print or cat my-files-to-change.txt where my-files-to-change.txt contains a list of full paths to files needing changes.

Upon a list of paths arriving via STDIN changeline will apply functions to test, and replace data. See test-transformers.js for a more serious example.

module.exports = [
  // JS
  {
    description: "Update bark to meow.",
    search: function(line){ if(line === 'bark') return true; },
    replace: function(line){ return 'meow' },
  },
  // ES6
  {
    description: "Update Bort to Bart.",
    search: line => line === 'Bort',
    replace: line => 'Bart',
  },
]

Usage: changeline options

Options:

  -h, --help                 output usage information
  -V, --version              output the version number

  -v, --verbose              Make changeline verbose

The CAS backup concept is similar to Content Addressable Storage prior to altering a file a copy is saved in ~/.changeline a simple index keeps track of hashes, timestamps and original file locations.

  -c, --cas                  Make cas backup before replacement. (recommended)
  --cas-home [path]          Path of cas backups (optional)

A plain old filename.ext.bak is available as well. -b, --backup Make backup before replacement. (optional) --backup-extension ext Extension to use for backup files (optional)

You must use the -r/-t flags to do useful things:

  -r, --replace              Perform replacement (required for actual replacement)
  -t, --transformers [path]  Transformer module. (required for specifying what to replace)

The transformer format is ES6 by default and very easy to manage:

module.exports = [
  {
    description: "Update Bort to Bart.",
    search: line => line === 'Bort', // return truthy value to trigger replace
    replace: line => 'Bart', // return updated line content
  },
]

Features and Concepts

Changeline accepts a list of files from the command line via STDIN. This means you can use operating system utilities for file search. example: find . -name test.html -print | changeline -t transformers.js -r -c;

Changeline uses es6 functions for searching an replacing, see transformers.js

Changeline makes backups see --help

Snippets

A quick non-destructive one-liner, run it in changeline's directory:

cp test.html test-tmp.html; echo -e "\nBEFORE"; cat test-tmp.html; echo; find . -name test-tmp.html -print | ./index.js -v -r -c -t ./test-transformers.js; echo -e "\nAFTER"; cat test-tmp.html; echo; rm test-tmp.html;