S3 commandline client s5cmd

In this page you will find documentation about an S3 client. Here we refer to buckets, this is the S3 term for containers. They are identical.


The tool s5cmd allows you to parallelise workloads like data transfers. This is very convenient when you want to copy a whole directory with its contents to an S3 bucket or vice versa. More information may be found at https://github.com/peak/s5cmd, https://joshua-robinson.medium.com/s5cmd-for-high-performance-object-storage-7071352cc09d and https://aws.amazon.com/blogs/opensource/parallelizing-s2-workloads-s5cmd/.

The key benefit of s5cmd is its greatly improved performance as compared to s3cmd and aws cli etc.


Binaries can be downloaded from: https://github.com/peak/s5cmd/releases for Windows, Mac and Linux.

For Openstack SWIFT, please use version 2.2.2 or above.


In order to authenticate you need the same as for the awscli client. See: http://doc.swift.surfsara.nl/en/latest/Pages/Clients/awscli.html#configuration.

Upload/Download an object to/from a bucket

First you need to setup the endpoint of the service as an environment variable:

export S3_ENDPOINT_URL=https://proxy.swift.surfsara.nl

An object can be uploaded to a bucket by the following command:

s5cmd cp <file name> s3://mybucket/myobject

It can be downloaded by:

s5cmd cp s3://mybucket/myobject <filename>

Upload a folder with contents to a bucket

s5cmd cp /path/to/my/folder s3://mybucket

Download a bucket with contents to a directory

s5cmd cp s3://mybucket/* /path/to/my/folder/.

Large files


Important: By default s5cmd spawns 256 workers to do its tasks in parallel. This tool is really well suited for transferring a large number of small files. For larger files (>= 1GB) we have found it beneficial to reduce the number of workers to a smaller number, like for example 20, in order to reduce the load on the client side. To do that use the commandline flag --numworkers <value>. An example is shown below:

s5cmd --numworkers 20 cp /path/to/my/folder/with/big/files s3://mybucket