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CLI version of CyberDuck

Getting Duck

This client is available at

Creating a config

Duck is used to move files, and handles a lot of different protocols, and for each of those protocols you use, it wants you to make a URL scheme so it can differentiate between endpoints in case you use it to copy from remoteA to remoteB. This in turn shares the config file format that Cyberduck uses, but since you would almost always configure Cyberduck from the GUI, it's not super well documented nor simple. For this reason we have made a config file that works with our S3 endpoints.

I've chosen the name safe:// for the endpoint, you can choose any other name of course. The filename isn't very important, but it needs to end in .cyberduckprofile in order for duck to pick it up. The protocol name is set in the Vendor part of the config file.

The config should be in your home folder, under


The contents of this file should look like this for the Norwegian site:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "
<plist version="1.0">
        <string>Safespring Storage</string>
        <key>Default Port</key>
        <key>Default Hostname</key>

Change the "Default Hostname" entry to for the Swedish site, everything else can be left as is.

The first time you connect to the service, it will ask you for the access_key and the secret_key:

$ duck --list safe://my-test-bucket/
Login – S3 with username and password.
No login credentials could be found in the Keychain.
Access Key ID (ubuntu): ABCDEFGHIJ
Secret Access Key: SECRETKEYGOESHERE12345678

Save password (y/n): y

How to run

The cli version of CyberDuck is mostly meant for scripting so it doesn't contain all the S3-related bells and whistles that for instance s3cmd does, so for changing fancy permissions on objects or other meta operations you should probably use the GUI or s3cmd, but for normal upload/download/sync ops, duck performs very well and allows for good parallelism while transferring data.

Lists entries in that bucket,

duck --list safe://<my-bucket-name>

Uploads a file or recursively uploads a whole directory structure.

duck --upload safe://my-bucket-name object-or-dir

Downloads it later on.

duck --download safe://my-bucket-name/file

Use this to synchronize local -vs- remote folders.

duck --synchronize safe://my-bucket-name local-dir


Adding --parallel <X> will use X parallel streams for sending data and a value between 5 or 10 might be suitable to speed things up a bit.

-e is used to tell duck how to handle overwrites if the destination already exists.

For Upload and Download the options include:

Resume, Overwrite, Rename (add timestamp), Skip, Compare, Cancel

and for Synchronize the options are:

Download, Upload, Mirror, Cancel

which tells the sync operation if local or remote side wins in case of changed files or if it should add changed or missing files both ways (Mirror).