`mc cat`

Syntax

The mc cat command concatenates the contents of a file or object to another file or object. You can also use the command to display the contents of the specified file or object to STDOUT. cat has similar functionality to cat.

EXAMPLE

The following command concatenates the contents of an object on a MinIO deployment to STDOUT:

mc cat play/mybucket/myobject.txt

SYNTAX

The mc cat command has the following syntax:

mc [GLOBALFLAGS] cat                       \
                 ALIAS [ALIAS ...]         \
                 [--enc-c "value"]         \
                 [--offset "int"]          \
                 [--part-number "int"]     \
                 [--rewind]                \
                 [--tail "int"]            \
                 [--version-id "string"]   \
                 [--zip]

Brackets [] indicate optional parameters.
Parameters sharing a line are mutually dependent.
Parameters separated using the pipe | operator are mutually exclusive.

Copy the example to a text editor and modify as-needed before running the command in the terminal/shell.

You can also use mc cat against a local filesystem to produce similar results to the cat commandline tool.

Parameters

ALIAS

Required

The alias of a MinIO deployment and the full path to the object. For example:

mc cat myminio/mybucket/myobject.txt

You can specify multiple objects on the same or different MinIO deployment. For example:

mc cat myminio/mybucket/object.txt myminio/myotherbucket/object.txt

For an object on a local filesystem, specify the full path to that object. For example:

mc cat ~/data/object.txt

--enc-c

Optional

Encrypt or decrypt objects using server-side SSE-C encryption with client-managed keys.

The parameter accepts a key-value pair formatted as KEY=VALUE

`KEY`	The full path to the object as `alias/bucket/path/object.ext`. You can specify only the top-level path to use a single encryption key for all operations in that path.
`VALUE`	Specify either a 32-byte RawBase64-encoded key or a 64-byte hex-encoded key for use with SSE-C encryption. Raw Base64 encoding rejects `=`-padded keys. Omit the padding or use a Base64 encoder that supports RAW formatting.

KEY

The full path to the object as alias/bucket/path/object.ext.

You can specify only the top-level path to use a single encryption key for all operations in that path.

VALUE

Specify either a 32-byte RawBase64-encoded key or a 64-byte hex-encoded key for use with SSE-C encryption.

Raw Base64 encoding rejects =-padded keys. Omit the padding or use a Base64 encoder that supports RAW formatting.

KEY - the full path to the object as alias/bucket/path/object.
VALUE - the 32-byte RAW Base64-encoded data key to use for encrypting object(s).

For example:

# RawBase64-Encoded string "mybucket32byteencryptionkeyssec"
--enc-c "myminio/mybucket/prefix/object.obj=bXlidWNrZXQzMmJ5dGVlbmNyeXB0aW9ua2V5c3NlYwo"

You can specify multiple encryption keys by repeating the parameter.

Specify the path to a prefix to apply encryption to all matching objects at that path:

--enc-c "myminio/mybucket/prefix/=bXlidWNrZXQzMmJ5dGVlbmNyeXB0aW9ua2V5c3NlYwo"

Note

MinIO strongly recommends against using SSE-C encryption in production workloads. Use SSE-KMS via the --enc-kms or SSE-S3 via --enc-s3 parameters instead.

--offset

Optional

Specify an integer that is the number of bytes from which the command offsets the output.

Mutually exclusive with the --part-number flag.

--part-number

Optional

Download a specific part number of a multi-part upload. Specify the integer of the part number to download.

Mutually exclusive with the --offset and --tail flags.

--rewind

Optional

Directs mc cat to operate only on the object version(s) that existed at specified point-in-time.

To rewind to a specific date in the past, specify the date as an ISO8601-formatted timestamp. For example: --rewind "2020.03.24T10:00".
To rewind a duration in time, specify the duration as a string in #d#hh#mm#ss format. For example: --rewind "1d2hh3mm4ss".

--rewind requires that the specified ALIAS be an S3-compatible service that supports Bucket Versioning. For MinIO deployments, use mc version to enable or disable bucket versioning.

--tail

Optional

Specify an integer that is the number of bytes from which the command trims the output.

Mutually exclusive with the --part-number flag.

--version-id, vid

Optional

Directs mc cat to operate only on the specified object version.

--version-id requires that the specified ALIAS be an S3-compatible service that supports Bucket Versioning. For MinIO deployments, use mc version to enable or disable bucket versioning.

--zip: Optional
Extracts the contents from a zip file on the source to the remote. Requires a MinIO deployment as the source ALIAS.

Global Flags

This command supports any of the global flags.

Examples

View an S3 Object

Use mc cat to return the object:

mc cat ALIAS/PATH

Replace ALIAS with the alias of the S3-compatible host.
Replace PATH with the path to the object on the S3-compatible host.

View an S3 Object at a Point-In-Time

Use mc cat --rewind to return the object at a specific point-in-time in the past:

mc cat ALIAS/PATH --rewind DURATION

Replace ALIAS with the alias of the S3-compatible host.
Replace PATH with the path to the object on the S3-compatible host.
Replace DURATION with the point-in-time in the past at which the command returns the object. For example, specify 30d to return the version of the object 30 days prior to the current date.

Requires Versioning

mc cat requires bucket versioning to use this feature. Use mc version to enable versioning on a bucket.

View an S3 Object with Specific Version

Use mc cat --version-id to return a specific version of the object:

mc cat ALIAS/PATH --version-id VERSION

Replace ALIAS with the alias of the S3-compatible host.
Replace PATH with the path to the object on the S3-compatible host.
Replace VERSION with the specific version of the object to return.

Requires Versioning

mc cat requires bucket versioning to use this feature. Use mc version to enable versioning on a bucket.

Download a particular part

Use mc cat --part-number to download a particular part of a multi-part upload:

mc cat ALIAS/PATH --part-number=#

Replace ALIAS with the alias of the S3-compatible host.
Replace PATH with the path to the object on the S3-compatible host.
Replace # with the integer of the part number to download. For example, to download part 3 of at 16-part multi-part file, use --part-number=3.

You cannot use the --part-number flag if you are using either the --offset or the --tail flags.

Behavior

S3 Compatibility

The mc commandline tool is built for compatibility with the AWS S3 API and is tested with MinIO and AWS S3 for expected functionality and behavior.

MinIO provides no guarantees for other S3-compatible services, as their S3 API implementation is unknown and therefore unsupported. While mc commands may work as documented, any such usage is at your own risk.