Official AWS CLI does support adding metadata such as --content-type and --cache-control.

$ aws s3 sync ./mydir/ s3://example-bucket/mydir/ \
--content-type 'application/rss+xml; charset=UTF-8' \
--cache-control 'max-age=86400'

The reason I need custom metadata is because I use S3 as static website hosting which sits behind Cloudfront. Setting correct origin headers such as cache-control and content-type for CDN/Proxy is important to my case.

How do I add custom metadata when uploading object using s5cmd? It seems I did not find the options.