du

Summarize object count and total size for a bucket or prefix.

Bucket summary

s3m du backup/backups

Prefix summary

s3m du backup/backups/2026/03/

Group by day

Group objects by the UTC calendar day derived from each object's LastModified value:

s3m du backup/backups --group-by day

This prints one row per day plus a final total row.

JSON output

Use --json for machine-readable output:

s3m du backup/backups --json

Grouped output can also be returned as JSON:

s3m du backup/backups --group-by day --json