本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

# 環境變數
<a name="example-use-envvars"></a>

下列範例任務定義使用環境變數來指定檔案類型和 Amazon S3 URL。此特定範例來自[建立簡單的「擷取和執行」 AWS Batch 任務](https://aws.amazon.com/blogs/compute/creating-a-simple-fetch-and-run-aws-batch-job/)運算部落格文章。部落格文章中描述的[https://github.com/awslabs/aws-batch-helpers/blob/master/fetch-and-run/fetch_and_run.sh](https://github.com/awslabs/aws-batch-helpers/blob/master/fetch-and-run/fetch_and_run.sh)指令碼使用這些環境變數從 S3 下載`myjob.sh`指令碼並宣告其檔案類型。

即使命令和環境變數在此範例中硬式編碼為任務定義，您也可以指定命令和環境變數覆寫，讓任務定義更多樣化。

```
{
    "jobDefinitionName": "fetch_and_run",
    "type": "container",
    "containerProperties": {
        "image": "{{123456789012}}.dkr.ecr.us-east-1.amazonaws.com/fetch_and_run",
        "resourceRequirements": [
            {
                "type": "MEMORY",
                "value": "2000"
            },
            {
                "type": "VCPU",
                "value": "2"
            }
        ],
        "command": [
            "myjob.sh",
            "60"
        ],
        "jobRoleArn": "arn:aws:iam::{{123456789012}}:role/AWSBatchS3ReadOnly",
        "environment": [
            {
                "name": "BATCH_FILE_S3_URL",
                "value": "s3://amzn-s3-demo-source-bucket/myjob.sh"
            },
            {
                "name": "BATCH_FILE_TYPE",
                "value": "script"
            }
        ],
        "user": "nobody"
    }
}
```