repo_description: :shell: Portable Unix shell commands for Node.js
repo_topics: bash javascript node nodejs shell shelljs unix
code: var fs = require('fs');
  var path = require('path');
  var common = require('./common');
  
  common.register('ln', _ln, {
    cmdOptions: {
      's': 'symlink',
      'f': 'force',
    },
  });
  
  //@
  //@ ### ln([options,] source, dest)
  //@
  //@ Available options:
  //@
  //@ + `-s`: symlink
  //@ + `-f`: force
  //@
  //@ Examples:
  //@
  //@ ```javascript
  //@ ln('file', 'newlink');
  //@ ln('-sf', 'file', 'existing');
  //@ ```
  //@
  //@ Links `source` to `dest`. Use `-f` to force the link, should `dest` already
  //@ exist. Returns a [ShellString](#shellstringstr) indicating success or
  //@ failure.
  function _ln(options, source, dest) {
    if (!source || !dest) {
      common.error('Missing <source> and/or <dest>');
    }
  
    source = String(source);
    var sourcePath = path.normalize(source).replace(RegExp(path.sep + '$'), '');
    var isAbsolute = (path.resolve(source) === sourcePath);
    dest = path.resolve(process.cwd(), String(dest));
  
    if (fs.existsSync(dest)) {
      if (!options.force) {
        common.error('Destination file exists', { continue: true });
      }
  
      fs.unlinkSync(dest);
    }
  
    if (options.symlink) {
      var isWindows = process.platform === 'win32';
      var linkType = isWindows ? 'file' : null;
      var resolvedSourcePath = isAbsolute ? sourcePath : path.resolve(process.cwd(), path.dirname(dest), source);
      if (!fs.existsSync(resolvedSourcePath)) {
        common.error('Source file does not exist', { continue: true });
      } else if (isWindows && common.statFollowLinks(resolvedSourcePath).isDirectory()) {
        linkType = 'junction';
      }
  
      try {
        fs.symlinkSync(linkType === 'junction' ? resolvedSourcePath : source, dest, linkType);
      } catch (err) {
        common.error(err.message);
      }
    } else {
      if (!fs.existsSync(source)) {
        common.error('Source file does not exist', { continue: true });
      }
      try {
        fs.linkSync(source, dest);
      } catch (err) {
        common.error(err.message);
      }
    }
    return '';
  }
  module.exports = _ln;
  