cp

Copy a file to the bucket:

aws s3 cp test.txt s3://amzn-demo/ --recursive
aws s3 cp test.txt s3://amzn-demo/ \
    --expires 2014-10-01T20:30:00Z
const fs = require('node:fs');
// read it back
fs.readFileSync('out.txt');
javascript
import fs from 'node:fs';
    def load(path):
        with open(path) as fh:
            return json.load(fh)

Pass the --recursive flag to copy a directory.

A period (.) means the working directory.