cp - Copy files and objects

Synopsis

gsutil cp [OPTION]... src_url dst_url
gsutil cp [OPTION]... src_url... dst_url
gsutil cp [OPTION]... -I dst_url

Description

The gsutil cp command allows you to copy data between your local file system and the cloud, within the cloud, and between cloud storage providers. For example, to upload all text files from the local directory to a bucket, you can run:

gsutil cp *.txt gs://my-bucket

You can also download text files from a bucket:

gsutil cp gs://my-bucket/*.txt .

Use the -r option to copy an entire directory tree. For example, to upload the directory tree dir:

gsutil cp -r dir gs://my-bucket

If you have a large number of files to transfer, you can perform a parallel multi-threaded/multi-processing copy using the top-level gsutil -m option (see gsutil help options):

gsutil -m cp -r dir gs://my-bucket

You can use the -I option with stdin to specify a list of URLs to copy, one per line. This allows you to use gsutil in a pipeline to upload or download objects as generated by a program:

cat filelist | gsutil -m cp -I gs://my-bucket

or:

cat filelist | gsutil -m cp -I ./download_dir

where the output of cat filelist is a list of files, cloud URLs, and wildcards of files and cloud URLs.

How Names Are Constructed

The gsutil cp command attempts to name objects in ways that are consistent with the Linux cp command. This means that names are constructed depending on whether you're performing a recursive directory copy or copying individually-named objects, or whether you're copying to an existing or non-existent directory.

When you perform recursive directory copies, object names are constructed to mirror the source directory structure starting at the point of recursive processing. For example, if dir1/dir2 contains the file a/b/c, then the following command creates the object gs://my-bucket/dir2/a/b/c:

gsutil cp -r dir1/dir2 gs://my-bucket

In contrast, copying individually-named files results in objects named by the final path component of the source files. For example, assuming again that dir1/dir2 contains a/b/c, the following command creates the object gs://my-bucket/c:

gsutil cp dir1/dir2/** gs://my-bucket

Note that in the above example, the '**' wildcard matches all names anywhere under dir. The wildcard '*' matches names just one level deep. For more details, see gsutil help wildcards.

The same rules apply for uploads and downloads: recursive copies of buckets and bucket subdirectories produce a mirrored filename structure, while copying individually or wildcard-named objects produce flatly-named files.

In addition, the resulting names depend on whether the destination subdirectory exists. For example, if gs://my-bucket/subdir exists as a subdirectory, the following command creates the object gs://my-bucket/subdir/dir2/a/b/c:

gsutil cp -r dir1/dir2 gs://my-bucket/subdir

In contrast, if gs://my-bucket/subdir does not exist, this same gsutil cp command creates the object gs://my-bucket/subdir/a/b/c.

Copying To/From Subdirectories; Distributing Transfers Across Machines

You can use gsutil to copy to and from subdirectories by using a command like this:

gsutil cp -r dir gs://my-bucket/data

This causes dir and all of its files and nested subdirectories to be copied under the specified destination, resulting in objects with names like gs://my-bucket/data/dir/a/b/c. Similarly, you can download from bucket subdirectories using the following command:

gsutil cp -r gs://my-bucket/data dir

This causes everything nested under gs://my-bucket/data to be downloaded into dir, resulting in files with names like dir/data/a/b/c.

Copying subdirectories is useful if you want to add data to an existing bucket directory structure over time. It's also useful if you want to parallelize uploads and downloads across multiple machines (potentially reducing overall transfer time compared with running gsutil -m cp on one machine). For example, if your bucket contains this structure:

gs://my-bucket/data/result_set_01/
gs://my-bucket/data/result_set_02/
...
gs://my-bucket/data/result_set_99/

you can perform concurrent downloads across 3 machines by running these commands on each machine, respectively:

gsutil -m cp -r gs://my-bucket/data/result_set_[0-3]* dir
gsutil -m cp -r gs://my-bucket/data/result_set_[4-6]* dir
gsutil -m cp -r gs://my-bucket/data/result_set_[7-9]* dir

Note that dir could be a local directory on each machine, or a directory mounted off of a shared file server. The performance of the latter depends on several factors, so we recommend experimenting to find out what works best for your computing environment.

Copying In The Cloud And Metadata Preservation

If both the source and destination URL are cloud URLs from the same provider, gsutil copies data "in the cloud" (without downloading to and uploading from the machine where you run gsutil). In addition to the performance and cost advantages of doing this, copying in the cloud preserves metadata such as Content-Type and Cache-Control. In contrast, when you download data from the cloud, it ends up in a file with no associated metadata, unless you have some way to keep or re-create that metadata.

Copies spanning locations and/or storage classes cause data to be rewritten in the cloud, which may take some time (but is still faster than downloading and re-uploading). Such operations can be resumed with the same command if they are interrupted, so long as the command parameters are identical.

Note that by default, the gsutil cp command does not copy the object ACL to the new object, and instead uses the default bucket ACL (see gsutil help defacl). You can override this behavior with the -p option.

When copying in the cloud, if the destination bucket has Object Versioning enabled, by default gsutil cp copies only live versions of the source object. For example, the following command causes only the single live version of gs://bucket1/obj to be copied to gs://bucket2, even if there are noncurrent versions of gs://bucket1/obj:

 gsutil cp gs://bucket1/obj gs://bucket2

To also copy noncurrent versions, use the ``-A`` flag:

 gsutil cp -A gs://bucket1/obj gs://bucket2

The top-level gsutil -m flag is not allowed when using the cp -A flag, to ensure that version ordering is preserved.

Checksum Validation

At the end of every upload or download, the gsutil cp command validates that the checksum it computes for the source file matches the checksum that the service computes. If the checksums do not match, gsutil deletes the corrupted object and prints a warning message. If this happens, contact gs-team@google.com.

If you know the MD5 of a file before uploading, you can specify it in the Content-MD5 header, which enables the cloud storage service to reject the upload if the MD5 doesn't match the value computed by the service. For example:

% gsutil hash obj
Hashing     obj:
Hashes [base64] for obj:
        Hash (crc32c):          lIMoIw==
        Hash (md5):             VgyllJgiiaRAbyUUIqDMmw==

% gsutil -h Content-MD5:VgyllJgiiaRAbyUUIqDMmw== cp obj gs://your-bucket/obj
Copying file://obj [Content-Type=text/plain]...
Uploading   gs://your-bucket/obj:                                182 b/182 B

If the checksums don't match, the service rejects the upload and
gsutil prints a message like:

BadRequestException: 400 Provided MD5 hash "VgyllJgiiaRAbyUUIqDMmw=="
doesn't match calculated MD5 hash "7gyllJgiiaRAbyUUIqDMmw==".

Specifying the Content-MD5 header has several advantages:

  1. It prevents the corrupted object from becoming visible. If you don't specify the header, the object is visible for 1-3 seconds before gsutil deletes it.
  2. If an object already exists with the given name, specifying the Content-MD5 header prevents the existing object from being replaced. Otherwise, the existing object is replaced by the corrupted object and deleted a few seconds later.
  3. If you don't specify the Content-MD5 header, it's possible for the gsutil process to complete the upload but then be interrupted or fail before it can delete the corrupted object, leaving the corrupted object in the cloud.
  4. It supports a customer-to-service integrity check handoff. For example, if you have a content production pipeline that generates data to be uploaded to the cloud along with checksums of that data, specifying the MD5 computed by your content pipeline when you run gsutil cp ensures that the checksums match all the way through the process. This way, you can detect if data gets corrupted on your local disk between the time it was written by your content pipeline and the time it was uploaded to Cloud Storage.

Retry Handling

The cp command retries when failures occur, but if enough failures happen during a particular copy or delete operation, the cp command skips that object and moves on. If any failures were not successfully retried by the end of the copy run, the cp command reports the number of failures, and exits with a non-zero status.

Note that there are cases where retrying never succeeds, such as if you have insufficient write permissions to the destination bucket, or if the destination path for an object is longer than the maximum allowed length.

For more details about gsutil's retry handling, see gsutil help retries.

Resumable Transfers

gsutil automatically performs a resumable upload whenever you use the cp command to upload an object that is larger than 8 MiB. You do not need to specify any special command line options to make this happen. If your upload is interrupted, you can restart the upload by running the same cp command that you used to start the upload. You can adjust the minimum size for performing resumable uploads by changing the resumable_threshold parameter in the boto configuration file.

Until the upload has completed successfully, it is not visible at the destination object and does not supersede any existing object the upload is intended to replace. However, parallel composite uploads may leave temporary component objects in place during the upload process.

Similarly, gsutil automatically performs resumable downloads using standard HTTP Range GET operations whenever you use the cp command, unless the destination is a stream. In this case, a partially downloaded temporary file is visible in the destination directory. Upon completion, the original file is deleted and replaced with the downloaded contents.

Resumable uploads and downloads store state information in files under ~/.gsutil, named by the destination object or file. If you attempt to resume a transfer from a machine with a different directory, the transfer starts over from scratch.

See gsutil help prod for details on using resumable transfers in production.

Streaming Transfers

Use '-' in place of src_url or dst_url to perform a streaming transfer. For example:

long_running_computation | gsutil cp - gs://my-bucket/obj

Streaming uploads using the JSON API (see gsutil help apis) are buffered in memory part-way back into the file and can thus retry in the event of network or service problems.

Streaming transfers using the XML API do not support resumable uploads or downloads. If you have a large amount of data to upload or download, over 100 MiB for example, we recommend that you write the data to a local file and copy that file rather than streaming it.

Sliced Object Downloads

gsutil uses HTTP Range GET requests to perform "sliced" downloads in parallel when downloading large objects from Cloud Storage. This means that disk space for the temporary download destination file is pre-allocated and byte ranges (slices) within the file are downloaded in parallel. Once all slices have completed downloading, the temporary file is renamed to the destination file. No additional local disk space is required for this operation.

This feature is only available for Cloud Storage objects because it requires a fast composable checksum (CRC32C) to verify the data integrity of the slices. Because sliced object downloads depend on CRC32C, they require a compiled crcmod on the machine performing the download. If compiled crcmod is not available, a non-sliced object download is performed instead.

Parallel Composite Uploads

gsutil can automatically use object composition to perform uploads in parallel for large, local files being uploaded to Cloud Storage. See the Uploads and downloads documentation for a complete discussion.

Changing Temp Directories

gsutil writes data to a temporary directory in several cases:

  • when compressing data to be uploaded (see the -z and -Z options)
  • when decompressing data being downloaded (for example, when the data has Content-Encoding:gzip as a result of being uploaded using gsutil cp -z or gsutil cp -Z)
  • when running integration tests using the gsutil test command

In these cases, it's possible the temporary file location on your system that gsutil selects by default may not have enough space. If gsutil runs out of space during one of these operations (for example, raising "CommandException: Inadequate temp space available to compress <your file>" during a gsutil cp -z operation), you can change where it writes these temp files by setting the TMPDIR environment variable. On Linux and macOS, you can set the variable as follows:

TMPDIR=/some/directory gsutil cp ...

You can also add this line to your ~/.bashrc file and restart the shell before running gsutil:

export TMPDIR=/some/directory

On Windows 7, you can change the TMPDIR environment variable from Start -> Computer -> System -> Advanced System Settings -> Environment Variables. You need to reboot after making this change for it to take effect. Rebooting is not necessary after running the export command on Linux and macOS.

Options

-a canned_acl Applies the specific canned_acl to uploaded objects. See "gsutil help acls" for further details.
-A

Copy all source versions from a source bucket or folder. If not set, only the live version of each source object is copied.

-c

If an error occurs, continue attempting to copy the remaining files. If any copies are unsuccessful, gsutil's exit status is non-zero, even if this flag is set. This option is implicitly set when running gsutil -m cp....

-D

Copy in "daisy chain" mode, which means copying between two buckets by first downloading to the machine where gsutil is run, then uploading to the destination bucket. The default mode is a "copy in the cloud," where data is copied between two buckets without uploading or downloading.

During a "copy in the cloud," a source composite object remains composite at its destination. However, you can use "daisy chain" mode to change a composite object into a non-composite object. For example:

gsutil cp -D -p gs://bucket/obj gs://bucket/obj_tmp
gsutil mv -p gs://bucket/obj_tmp gs://bucket/obj
-e Exclude symlinks. When specified, symbolic links are not copied.
-I

Use stdin to specify a list of files or objects to copy. You can use gsutil in a pipeline to upload or download objects as generated by a program. For example:

cat filelist | gsutil -m cp -I gs://my-bucket

where the output of cat filelist is a one-per-line list of files, cloud URLs, and wildcards of files and cloud URLs.

-j <ext,...>

Applies gzip transport encoding to any file upload whose extension matches the -j extension list. This is useful when uploading files with compressible content such as .js, .css, or .html files. This also saves network bandwidth while leaving the data uncompressed in Cloud Storage.

When you specify the -j option, files being uploaded are compressed in-memory and on-the-wire only. Both the local files and Cloud Storage objects remain uncompressed. The uploaded objects retain the Content-Type and name of the original files.

Note that if you want to use the top-level -m option to parallelize copies along with the -j/-J options, your performance may be bottlenecked by the "max_upload_compression_buffer_size" boto config option, which is set to 2 GiB by default. You can change this compression buffer size to a higher limit. For example:

gsutil -o "GSUtil:max_upload_compression_buffer_size=8G" \
  -m cp -j html,txt -r /local/source/dir gs://bucket/path
-J

Applies gzip transport encoding to file uploads. This option works like the -j option described above, but it applies to all uploaded files, regardless of extension.

-L <file>

Outputs a manifest log file with detailed information about each item that was copied. This manifest contains the following information for each item:

  • Source path.
  • Destination path.
  • Source size.
  • Bytes transferred.
  • MD5 hash.
  • Transfer start time and date in UTC and ISO 8601 format.
  • Transfer completion time and date in UTC and ISO 8601 format.
  • Upload id, if a resumable upload was performed.
  • Final result of the attempted transfer, either success or failure.
  • Failure details, if any.

If the log file already exists, gsutil uses the file as an input to the copy process, and appends log items to the existing file. Objects that are marked in the existing log file as having been successfully copied or skipped are ignored. Objects without entries are copied and ones previously marked as unsuccessful are retried. This option can be used in conjunction with the -c option to build a script that copies a large number of objects reliably, using a bash script like the following:

until gsutil cp -c -L cp.log -r ./dir gs://bucket; do
  sleep 1
done

The -c option enables copying to continue after failures occur, and the -L option allows gsutil to pick up where it left off without duplicating work. The loop continues running as long as gsutil exits with a non-zero status. A non-zero status indicates there was at least one failure during the copy operation.

-n No-clobber. When specified, existing files or objects at the destination are not replaced. Any items that are skipped by this option are reported as skipped. gsutil performs an additional GET request to check if an item exists before attempting to upload the data. This saves gsutil from retransmitting data, but the additional HTTP requests may make small object transfers slower and more expensive.
-p

Preserves ACLs when copying in the cloud. Note that this option has performance and cost implications only when using the XML API, as the XML API requires separate HTTP calls for interacting with ACLs. You can mitigate this performance issue using gsutil -m cp to perform parallel copying. Note that this option only works if you have OWNER access to all objects that are copied. If you want all objects in the destination bucket to end up with the same ACL, you can avoid these performance issues by setting a default object ACL on that bucket instead of using cp -p. See gsutil help defacl.

Note that it's not valid to specify both the -a and -p options together.

-P

Enables POSIX attributes to be preserved when objects are copied. gsutil cp copies fields provided by stat. These fields are the user ID of the owner, the group ID of the owning group, the mode or permissions of the file, and the access and modification time of the file. For downloads, these attributes are only set if the source objects were uploaded with this flag enabled.

On Windows, this flag only sets and restores access time and modification time. This is because Windows doesn't support POSIX uid/gid/mode.

-R, -r The -R and -r options are synonymous. They enable directories, buckets, and bucket subdirectories to be copied recursively. If you don't use this option for an upload, gsutil copies objects it finds and skips directories. Similarly, if you don't specify this option for a download, gsutil copies objects at the current bucket directory level and skips subdirectories.
-s <class> Specifies the storage class of the destination object. If not specified, the default storage class of the destination bucket is used. This option is not valid for copying to non-cloud destinations.
-U Skips objects with unsupported object types instead of failing. Unsupported object types include Amazon S3 objects in the GLACIER storage class.
-v Prints the version-specific URL for each uploaded object. You can use these URLs to safely make concurrent upload requests, because Cloud Storage refuses to perform an update if the current object version doesn't match the version-specific URL. See gsutil help versions for more details.
-z <ext,...>

Applies gzip content-encoding to any file upload whose extension matches the -z extension list. This is useful when uploading files with compressible content such as .js, .css, or .html files, because it reduces network bandwidth and storage sizes. This can both improve performance and reduce costs.

When you specify the -z option, the data from your files is compressed before it is uploaded, but your actual files are left uncompressed on the local disk. The uploaded objects retain the Content-Type and name of the original files, but are given a Content-Encoding header with the value gzip to indicate that the object data stored are compressed on the Cloud Storage servers.

For example, the following command:

gsutil cp -z html -a public-read \
  cattypes.html tabby.jpeg gs://mycats

does the following:

  • The cp command uploads the files cattypes.html and
    tabby.jpeg to the bucket gs://mycats.
  • Based on the file extensions, gsutil sets the Content-Type
    of cattypes.html to text/html and tabby.jpeg to image/jpeg.
  • The -z option compresses the data in the file cattypes.html.
  • The -z option also sets the Content-Encoding for
    cattypes.html to gzip.
  • The -a option sets the ACL for both files to public-read.
  • If a user tries to view cattypes.html in a browser, the browser uncompresses the data based on the Content-Encoding header and renders it as HTML based on the Content-Type header.

Because the -z/-Z options compress data prior to upload, they are not subject to the same compression buffer bottleneck that can affect the -j/-J options.

Note that if you download an object with Content-Encoding:gzip, gsutil decompresses the content before writing the local file.

-Z

Applies gzip content-encoding to file uploads. This option works like the -z option described above, but it applies to all uploaded files, regardless of extension.