S3cmd tool for Amazon Simple Storage Service (S3)

    Michal Ludvig <michal@logix.cz>

S3tools / S3cmd project homepage:

S3tools / S3cmd mailing list:

Amazon S3 homepage:

!!! Please consult INSTALL file for installation instructions!

What is Amazon S3
Amazon S3 provides a managed internet-accessible storage 
service where anyone can store any amount of data and 
retrieve it later again. Maximum amount of data in one 
"object" is 5GB, maximum number of objects is not limited.

S3 is a paid service operated by the well known Amazon.com
internet book shop. Before storing anything into S3 you
must sign up for an "AWS" account (where AWS = Amazon Web 
Services) to obtain a pair of identifiers: Access Key and
Secret Key. You will need to give these keys to S3cmd. 
Think of them as if they were a username and password for
your S3 account.

Pricing explained
At the time of this writing the costs of using S3 are (in USD):

$0.15 per GB per month of storage space used


$0.10 per GB - all data uploaded


$0.18 per GB - first 10 TB / month data downloaded
$0.16 per GB - next 40 TB / month data downloaded
$0.13 per GB - data downloaded / month over 50 TB


$0.01 per 1,000 PUT or LIST requests
$0.01 per 10,000 GET and all other requests

If for instance on 1st of January you upload 2GB of 
photos in JPEG from your holiday in New Zealand, at the 
end of January you will be charged $0.30 for using 2GB of
storage space for a month, $0.20 for uploading 2GB
of data, and a few cents for requests. 
That comes to slightly over $0.50 for a complete backup 
of your precious holiday pictures.

In February you don't touch it. Your data are still on S3 
servers so you pay $0.30 for those two gigabytes, but not
a single cent will be charged for any transfer. That comes 
to $0.30 as an ongoing cost of your backup. Not too bad.

In March you allow anonymous read access to some of your
pictures and your friends download, say, 500MB of them. 
As the files are owned by you, you are responsible for the 
costs incurred. That means at the end of March you'll be 
charged $0.30 for storage plus $0.09 for the download traffic 
generated by your friends.

There is no minimum monthly contract or a setup fee. What 
you use is what you pay for. At the beginning my bill used
to be like US$0.03 or even nil.

That's the pricing model of Amazon S3 in a nutshell. Check
Amazon S3 homepage at http://aws.amazon.com/s3 for more 

Needless to say that all these money are charged by Amazon 
itself, there is obviously no payment for using S3cmd :-)

Amazon S3 basics
Files stored in S3 are called "objects" and their names are 
officially called "keys". Each object belongs to exactly one
"bucket". Buckets are kind of directories or folders with 
some restrictions: 1) each user can only have 100 buckets at 
the most, 2) bucket names must be unique amongst all users 
of S3, 3) buckets can not be nested into a deeper
hierarchy and 4) a name of a bucket can only consist of basic 
alphanumeric characters plus dot (.) and dash (-). No spaces,
no accented or UTF-8 letters, etc.

On the other hand there are almost no restrictions on object 
names ("keys"). These can be any UTF-8 strings of up to 1024 
bytes long. Interestingly enough the object name can contain
forward slash character (/) thus a "my/funny/picture.jpg" is
a valid object name. Note that there are not directories nor
buckets called "my" and "funny" - it is really a single object 
name called "my/funny/picture.jpg" and S3 does not care at 
all that it _looks_ like a directory structure.

To describe objects in S3 storage we invented a URI-like
schema in the following form:


See the HowTo later in this document for example usages of 
this S3-URI schema.

Simple S3cmd HowTo
1) Register for Amazon AWS / S3
   Go to http://aws.amazon.com/s3, click the "Sign up
   for web service" button in the right column and work 
   through the registration. You will have to supply 
   your Credit Card details in order to allow Amazon 
   charge you for S3 usage. 
   At the end you should posses your Access and Secret Keys

2) Run "s3cmd --configure"
   You will be asked for the two keys - copy and paste 
   them from your confirmation email or from your Amazon 
   account page. Be careful when copying them! They are 
   case sensitive and must be entered accurately or you'll 
   keep getting errors about invalid signatures or similar.

3) Run "s3cmd ls" to list all your buckets.
   As you just started using S3 there are no buckets owned by 
   you as of now. So the output will be empty.

4) Make a bucket with "s3cmd mb s3://my-new-bucket-name"
   As mentioned above bucket names must be unique amongst 
   _all_ users of S3. That means the simple names like "test" 
   or "asdf" are already taken and you must make up something 
   more original. I sometimes prefix my bucket names with
   my e-mail domain name (logix.cz) leading to a bucket name,
   for instance, 'logix.cz-test':

   ~$ s3cmd mb s3://logix.cz-test
   Bucket 'logix.cz-test' created

5) List your buckets again with "s3cmd ls"
   Now you should see your freshly created bucket

   ~$ s3cmd ls
   2007-01-19 01:41  s3://logix.cz-test

6) List the contents of the bucket

   ~$ s3cmd ls s3://logix.cz-test
   Bucket 'logix.cz-test':

   It's empty, indeed.

7) Upload a file into the bucket

   ~$ s3cmd put addressbook.xml s3://logix.cz-test/addrbook.xml
   File 'addressbook.xml' stored as s3://logix.cz-test/addrbook.xml (123456 bytes)

8) Now we can list the bucket contents again

   ~$ s3cmd ls s3://logix.cz-test
   Bucket 'logix.cz-test':
   2007-01-19 01:46       120k  s3://logix.cz-test/addrbook.xml

9) Retrieve the file back and verify that its hasn't been 

   ~$ s3cmd get s3://logix.cz-test/addrbook.xml addressbook-2.xml
   Object s3://logix.cz-test/addrbook.xml saved as 'addressbook-2.xml' (123456 bytes)

   ~$ md5sum addressbook.xml addressbook-2.xml
   39bcb6992e461b269b95b3bda303addf  addressbook.xml
   39bcb6992e461b269b95b3bda303addf  addressbook-2.xml

   Checksums of the original file matches the one of the 
   retrieved one. Looks like it worked :-)

10) Clean up: delete the object and remove the bucket

   ~$ s3cmd rb s3://logix.cz-test
   ERROR: S3 error: 409 (Conflict): BucketNotEmpty

   Ouch, we can only remove empty buckets!

   ~$ s3cmd del s3://logix.cz-test/addrbook.xml
   Object s3://logix.cz-test/addrbook.xml deleted

   ~$ s3cmd rb s3://logix.cz-test
   Bucket 'logix.cz-test' removed

The basic usage is as simple as described in the previous 

You can increase the level of verbosity with -v option and 
if you're really keen to know what the program does under 
its bonet run it with -d to see all 'debugging' output.

After configuring it with --configure all available options
are spitted into your ~/.s3cfg file. It's a text file ready
to be modified in your favourite text editor. 

Multiple local files may be specified for "s3cmd put" 
operation. In that case the S3 URI should only include
the bucket name, not the object part:

~$ s3cmd put file-* s3://logix.cz-test/
File 'file-one.txt' stored as s3://logix.cz-test/file-one.txt (4 bytes)
File 'file-two.txt' stored as s3://logix.cz-test/file-two.txt (4 bytes)

Alternatively if you specify the object part as well it 
will be treated as a prefix and all filenames given on the
command line will be appended to the prefix making up 
the object name. However --force option is required in this

~$ s3cmd put --force file-* s3://logix.cz-test/prefixed:
File 'file-one.txt' stored as s3://logix.cz-test/prefixed:file-one.txt (4 bytes)
File 'file-two.txt' stored as s3://logix.cz-test/prefixed:file-two.txt (4 bytes)

This prefixing mode works with "s3cmd ls" as well:

~$ s3cmd ls s3://logix.cz-test
Bucket 'logix.cz-test':
2007-01-19 02:12         4   s3://logix.cz-test/file-one.txt
2007-01-19 02:12         4   s3://logix.cz-test/file-two.txt
2007-01-19 02:12         4   s3://logix.cz-test/prefixed:file-one.txt
2007-01-19 02:12         4   s3://logix.cz-test/prefixed:file-two.txt

Now with a prefix to list only names beginning with "file-":

~$ s3cmd ls s3://logix.cz-test/file-*
Bucket 'logix.cz-test':
2007-01-19 02:12         4   s3://logix.cz-test/file-one.txt
2007-01-19 02:12         4   s3://logix.cz-test/file-two.txt

For more information refer to:
* S3cmd / S3tools homepage at http://s3tools.sourceforge.net
* Amazon S3 homepage at http://aws.amazon.com/s3


Michal Ludvig
* michal@logix.cz
* http://www.logix.cz/michal