mc head

Syntax

The mc head command displays the first n lines of an object, where n is an argument specified to the command.

mc head does not perform any transformation or formatting of object contents to facilitate readability. You can also use mc head against the local filesystem to produce similar results to the head commandline tool.

• EXAMPLE
• SYNTAX

mc head myminio/mydata/myobject.txt

mc [GLOBALFLAGS] head                     \
                 [--lines int]            \
                 [--rewind "string"]      \
                 [--version-id "string"]  \
                 [--enc-c "string"]       \
                 ALIAS [ALIAS ...]

Parameters

ALIAS

mc-cmd

Required

The object or objects to print.

For an object on MinIO, specify the alias and the full path to that object (e.g. bucket and path to object). For example:

mc head play/mybucket/object.txt

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

mc head ~/mydata/object.txt myminio/mydata/object.txt

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

mc head ~/mydata/object.txt

--lines, n

mc-cmd

Optional

The number of lines to print.

Defaults to 10.

--enc-c

mc-cmd

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.
• 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"

--rewind

mc-cmd

Optional

Directs mc head 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.

--version-id, vid

mc-cmd

Optional

Directs mc head 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.

Global Flags

This command supports any of the global flags.

Examples

View Partial Contents of an Object

Use mc head to return the first 10 lines of an object:

mc head 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 Partial Contents of an Object at a Point in Time

Use mc head --rewind to return the first 10 lines of the object at a specific point-in-time in the past:

mc head 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.

View Partial Contents of an Object with Specific Version

Use mc head --version-id to return the first 10 lines of the object at a specific point-in-time in the past:

mc head 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 version of the object. For example, specify 30d to return the version of the object 30 days prior to the current date.

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.