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    Object Storage Service:append-object

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    Object Storage Service:append-object

    Last Updated:Dec 06, 2025

    The append-object command appends data to an object.

    Usage notes

    • The final object created using the append-object command cannot exceed 5 GB.

    • The append-object command does not support server-side encryption with Key Management Service (KMS) using a specified customer master key (CMK) ID.

    Permissions

    By default, an Alibaba Cloud account has full permissions. RAM users or RAM roles under an Alibaba Cloud account do not have any permissions by default. The Alibaba Cloud account or account administrator must grant operation permissions through RAM Policy or Bucket policies.

    API

    Action

    Definition

    AppendObject

    oss:PutObject

    You can call this operation to upload an object by appending the object to an existing object.

    oss:PutObjectTagging

    When uploading an object by appending the object to an existing object, if you specify object tags through x-oss-tagging, this permission is required.

    Command syntax

    ossutil api append-object --bucket value --key value --position value [flags]

    Parameter

    Type

    Description

    --body

    string

    The request body.

    --bucket

    string

    The name of the bucket.

    --cache-control

    string

    The web page caching behavior of the object.

    --content-disposition

    string

    The name of the object when it is downloaded.

    --content-encoding

    string

    The encoding format of the object content.

    --content-md5

    string

    The MD5 hash of the object content. This request header is used to check whether the message content is the same as the content that was sent.

    --expires

    string

    The expiration time.

    --key

    string

    The full path of the object.

    --metadata

    stringArray

    The metadata of the object. To specify custom metadata, configure parameters that are prefixed with x-oss-meta-*.

    --object-acl

    string

    The access control list (ACL) of the object.

    --position

    string

    The position from which to start appending data.

    --server-side-encryption

    string

    The server-side encryption method.

    --storage-class

    string

    The storage class of the object.

    --tagging

    string

    The tags of the object. You can specify multiple tags. Example: TagA=A&TagB=B.

    Note

    • The append-object command corresponds to the AppendObject API operation. For more information about the parameters of the API operation, see AppendObject.

    • For more information about supported global command-line options, see Global command-line options.

    Examples

    • Append data from a string to the object named exampleobject.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss"

    • Append data from a file to the object named exampleobject.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body file://appendFile

    • Append data from a string to the object named exampleobject and include custom metadata.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --metadata user=aliyun --metadata email=ali***@aliyuncs.com

    • Append data from a string to the object named exampleobject and specify object tags.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --tagging "TagA=A&TagB=B"

    • Append data from a string to the object named exampleobject and specify the access control list (ACL) and storage class of the object.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --object-acl private --storage-class IA

    • Append data from a string to the object named exampleobject and specify the server-side encryption method.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --body "hi oss" --server-side-encryption AES256

    • Append data from a string and specify the web page caching behavior for the object when it is downloaded.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --cache-control no-cache

    • Append data from a string and specify the filename of the object when it is downloaded.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --content-disposition "attachment;filename=oss_download.jpg"

    • Append data from a string to the object named exampleobject and specify the Content-MD5 hash of the object.

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --content-md5 ohhnqLBJFiKkPSBO1eNaUA==