Amazon S3 Tools: Command Line S3 Client Software and S3 Backup AWS S3 Command Line Clients for Windows, Linux, Mac. Backup to S3, upload, retrieve, query data on Amazon S3. Program S3cmd can transfer files to and from Amazon S3 in two basic modes: Unconditional transfer — all matching files are uploaded to S3 (put operation) or downloaded back from S3 (get operation). This is similar to a standard