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S3cmd tool for Amazon Simple Storage Service (S3)
Michal Ludvig <>
S3tools / S3cmd project homepage:
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* General questions and discussion about usage
* Bug reports
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
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 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". Since this is sometimes confusing
for the users we often refer to the objects as "files" or
"remote files". Each object belongs to exactly one "bucket".
To describe objects in S3 storage we invented a URI-like
schema in the following form:
Buckets are sort of like directories or folders with some
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.
It is a good idea to use DNS-compatible bucket names. That
for instance means you should not use upper case characters.
While DNS compliance is not strictly required some features
described below are not available for DNS-incompatible named
buckets. One more step further is using a fully qualified
domain name (FQDN) for a bucket - that has even more benefits.
* For example "s3://--My-Bucket--" is not DNS compatible.
* On the other hand "s3://my-bucket" is DNS compatible but
is not FQDN.
* Finally "s3://" is DNS compatible
and FQDN provided you own the domain and can
create the domain record for "".
Look for "Virtual Hosts" later in this text for more details
regarding FQDN named buckets.
Objects (files stored in Amazon S3)
Unlike for buckets there are almost no restrictions on object
names. 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.
The full URI of such an image could be, for example:
Public vs Private files
The files stored in S3 can be either Private or Public. The
Private ones are readable only by the user who uploaded them
while the Public ones can be read by anyone. Additionally the
Public files can be accessed using HTTP protocol, not only
using s3cmd or a similar tool.
The ACL (Access Control List) of a file can be set at the
time of upload using --acl-public or --acl-private options
with 's3cmd put' or 's3cmd sync' commands (see below).
Alternatively the ACL can be altered for existing remote files
with 's3cmd setacl --acl-public' (or --acl-private) command.
Simple s3cmd HowTo
1) Register for Amazon AWS / S3
Go to, 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 have 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 the 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. To demonstrate as many features as possible
let's create a FQDN-named bucket s3://
~$ s3cmd mb s3://
Bucket 's3://' created
5) List your buckets again with "s3cmd ls"
Now you should see your freshly created bucket
~$ s3cmd ls
2009-01-28 12:34 s3://
6) List the contents of the bucket
~$ s3cmd ls s3://
It's empty, indeed.
7) Upload a single file into the bucket:
~$ s3cmd put some-file.xml s3://
some-file.xml -> s3:// [1 of 1]
123456 of 123456 100% in 2s 51.75 kB/s done
Upload a two directory tree into the bucket's virtual 'directory':
~$ s3cmd put --recursive dir1 dir2 s3://
File 'dir1/file1-1.txt' stored as 's3://' [1 of 5]
File 'dir1/file1-2.txt' stored as 's3://' [2 of 5]
File 'dir1/file1-3.log' stored as 's3://' [3 of 5]
File 'dir2/file2-1.bin' stored as 's3://' [4 of 5]
File 'dir2/file2-2.txt' stored as 's3://' [5 of 5]
As you can see we didn't have to create the /somewhere
'directory'. In fact it's only a filename prefix, not
a real directory and it doesn't have to be created in
any way beforehand.
8) Now list the bucket contents again:
~$ s3cmd ls s3://
DIR s3://
2009-02-10 05:10 123456 s3://
Use --recursive (or -r) to list all the remote files:
~$ s3cmd ls s3://
2009-02-10 05:10 123456 s3://
2009-02-10 05:13 18 s3://
2009-02-10 05:13 8 s3://
2009-02-10 05:13 16 s3://
2009-02-10 05:13 11 s3://
2009-02-10 05:13 8 s3://
9) Retrieve one of the files back and verify that it hasn't been
~$ s3cmd get s3:// some-file-2.xml
s3:// -> some-file-2.xml [1 of 1]
123456 of 123456 100% in 3s 35.75 kB/s done
~$ md5sum some-file.xml some-file-2.xml
39bcb6992e461b269b95b3bda303addf some-file.xml
39bcb6992e461b269b95b3bda303addf some-file-2.xml
Checksums of the original file matches the one of the
retrieved one. Looks like it worked :-)
To retrieve a whole 'directory tree' from S3 use recursive get:
~$ s3cmd get --recursive s3://
File s3:// saved as './somewhere/dir1/file1-1.txt'
File s3:// saved as './somewhere/dir1/file1-2.txt'
File s3:// saved as './somewhere/dir1/file1-3.log'
File s3:// saved as './somewhere/dir2/file2-1.bin'
File s3:// saved as './somewhere/dir2/file2-2.txt'
Since the destination directory wasn't specified s3cmd
saved the directory structure in a current working
directory ('.').
There is an important difference between:
get s3://
get s3://
(note the trailing slash)
S3cmd always uses the last path part, ie the word
after the last slash, for naming files.
In the case of s3://.../somewhere the last path part
is 'somewhere' and therefore the recursive get names
the local files as somewhere/dir1, somewhere/dir2, etc.
On the other hand in s3://.../somewhere/ the last path
part is empty and s3cmd will only create 'dir1' and 'dir2'
without the 'somewhere/' prefix:
~$ s3cmd get --recursive s3:// /tmp
File s3:// saved as '/tmp/dir1/file1-1.txt'
File s3:// saved as '/tmp/dir1/file1-2.txt'
File s3:// saved as '/tmp/dir1/file1-3.log'
File s3:// saved as '/tmp/dir2/file2-1.bin'
See? It's /tmp/dir1 and not /tmp/somewhere/dir1 as it
was in the previous example.
10) Clean up - delete the remote files and remove the bucket:
Remove everything under s3://
~$ s3cmd del --recursive s3://
File s3:// deleted
File s3:// deleted
Now try to remove the bucket:
~$ s3cmd rb s3://
ERROR: S3 error: 409 (BucketNotEmpty): The bucket you tried to delete is not empty
Ouch, we forgot about s3://
We can force the bucket removal anyway:
~$ s3cmd rb --force s3://
WARNING: Bucket is not empty. Removing all the objects from it first. This may take some time...
File s3:// deleted
Bucket 's3://' 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.
For more information refer to:
* S3cmd / S3tools homepage at
* Amazon S3 homepage at
Michal Ludvig