Renames files to their md5 value of their content.

rnmd5.js

const path = require('path');
const fs = require('fs').promises;
const md5 = require('md5');
const uuid = require('uuid/v5');
const argv = require('yargs')
  .strict()
  .usage('$0 <files...>', 'Rename files to their md5 value.', (yargs) => {
    yargs.positional('files', {
      describe: 'The files that will be renamed.',
      type: 'array'
    })
  })
  .option('base64', {
    demand: false,
    default: false,
    type: 'boolean',
    description: 'Use base64 instead of hexadecimal.',
  })
  .option('slice-left', {
    demand: false,
    default: 0,
    type: 'number',
    description: 'Trim left of the filename by X characters.',
  })
  .option('slice-right', {
    demand: false,
    default: 0,
    type: 'number',
    description: 'Trim right of the filename by X characters.',
  })
  .option('hash', {
    demand: false,
    default: null,
    type: 'string',
    description: 'Use UUID v5 instead of MD5.',
  })
  .alias('v', 'version')
  .alias('h', 'help')
  .alias('b', 'base64')
  .alias('L', 'trim-left')
  .alias('R', 'trim-right')
  .alias('H', 'hash')
  .argv;

Promise.all(argv.files.map(async file => {
  try {
    let fileMd5 = md5(await fs.readFile(file));
    if (argv.hash) {
      fileMd5 = uuid(argv.hash, fileMd5, Buffer.alloc(16)).toString('hex');
    }
    if (argv.base64) {
      fileMd5 = Buffer.from(fileMd5, 'hex').toString('base64').replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '')
    }
    if (argv.trimLeft || argv.trimRight) {
      fileMd5 = fileMd5.slice(argv.trimLeft, argv.trimRight || fileMd5.length);
    }
    fileMd5 += path.extname(file);
    await fs.rename(file, path.join(path.dirname(file), fileMd5));
    console.log('%s --> %s', file, fileMd5);
  } catch (e) {
    console.error(e);
  }
})).then(()=> console.log('done!'));