Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Load Amazon CLI parameters from a file

Some parameters expect file names as arguments, from which the Amazon CLI loads the data. Other parameters enable you to specify the parameter value as either text typed on the command line or read from a file. Whether a file is required or optional, you must encode the file correctly so that the Amazon CLI can understand it. The file's encoding must match the reading system's default locale. You can determine this by using the Python locale.getpreferredencoding() method.

How to load parameters from a file

Sometimes it's convenient to load a parameter value from a file instead of trying to type it all as a command line parameter value, such as when the parameter is a complex JSON string. To specify a file that contains the value, specify a file URL in the following format.

file://complete/path/to/file

The file paths in the following examples are interpreted to be relative to the current working directory.

Linux or macOS

// Read from a file in the current directory
$ aws ec2 describe-instances --filters file://filter.json

// Read from a file in /tmp
$ aws ec2 describe-instances --filters file:///tmp/filter.json

// Read from a file with a filename with whitespaces
$ aws ec2 describe-instances --filters 'file://filter content.json'

Windows command prompt

// Read from a file in C:\temp
C:\> aws ec2 describe-instances --filters file://C:\temp\filter.json

// Read from a file with a filename with whitespaces
C:\> aws ec2 describe-instances --filters "file://C:\temp\filter content.json"

The file:// prefix option supports Unix-style expansions, including "~/", "./", and "../". On Windows, the "~/" expression expands to your user directory, stored in the %USERPROFILE% environment variable. For example, on Windows 10 you would typically have a user directory under C:\Users\UserName\.

You must still escape JSON documents that are embedded as the value of another JSON document.

$ aws sqs create-queue --queue-name my-queue --attributes file://attributes.json

attributes.json

{
  "RedrivePolicy": "{\"deadLetterTargetArn\":\"arn:aws-cn:sqs:us-west-2:0123456789012:deadletter\", \"maxReceiveCount\":\"5\"}"
}

Binary files

For commands that take binary data as a parameter, specify that the data is binary content by using the fileb:// prefix. Commands that accept binary data include:

The following example generates a binary 256-bit AES key using a Linux command line tool, and then provides it to Amazon S3 to encrypt an uploaded file server-side.

$ dd if=/dev/urandom bs=1 count=32 > sse.key
32+0 records in
32+0 records out
32 bytes (32 B) copied, 0.000164441 s, 195 kB/s
$ aws s3api put-object \
    --bucket my-bucket \
    --key test.txt \
    --body test.txt \
    --sse-customer-key fileb://sse.key \
    --sse-customer-algorithm AES256
{
    "SSECustomerKeyMD5": "iVg8oWa8sy714+FjtesrJg==",
    "SSECustomerAlgorithm": "AES256",
    "ETag": "\"a6118e84b76cf98bf04bbe14b6045c6c\""
}

For another example referencing a file containing JSON-formatted parameters, see Attach an IAM managed policy to a user.