Uploading and downloading objects in AWS - Commands & Configuration

Introduction

Sometimes you need to save files in the cloud or get them back later. Uploading means sending your files to cloud storage. Downloading means getting those files back to your computer.

When you want to save photos from your phone to cloud storage for backup.

When you need to share a document with your team using cloud storage.

When your app needs to store user files safely in the cloud.

When you want to download a report generated and saved in cloud storage.

When you want to move files between your computer and cloud storage quickly.

Commands

This command uploads the file 'myphoto.jpg' from your computer to the cloud storage bucket named 'example-bucket'.

Terminal

aws s3 cp myphoto.jpg s3://example-bucket/myphoto.jpg

Expected Output

upload: ./myphoto.jpg to s3://example-bucket/myphoto.jpg

→

--acl - Set access permissions for the uploaded file

This command downloads the file 'myphoto.jpg' from the cloud storage bucket to your computer and saves it as 'downloaded-photo.jpg'.

Terminal

aws s3 cp s3://example-bucket/myphoto.jpg downloaded-photo.jpg

Expected Output

download: s3://example-bucket/myphoto.jpg to ./downloaded-photo.jpg

This command lists all files inside the 'example-bucket' to check what is stored there.

Terminal

aws s3 ls s3://example-bucket/

Expected Output

2024-06-01 12:00:00      12345 myphoto.jpg

Key Concept

If you remember nothing else from this pattern, remember: use 'aws s3 cp' to copy files to and from cloud storage buckets.

Common Mistakes

Using the wrong bucket name or file path in the command

The command will fail because it cannot find the file or bucket specified.

Double-check the bucket name and file path before running the command.

Not having AWS credentials configured

The AWS CLI will not be able to authenticate and will return an error.

Run 'aws configure' to set up your access key, secret key, and region.

Trying to upload a file without read permission

The upload will fail because the CLI cannot read the local file.

Ensure the file has proper read permissions before uploading.

Summary

Use 'aws s3 cp' to upload files from your computer to an S3 bucket.

Use 'aws s3 cp' to download files from an S3 bucket to your computer.

Use 'aws s3 ls' to list files inside an S3 bucket.

Practice

1. What does uploading an object to an AWS S3 bucket mean?

easy

A. Deleting a file from the cloud storage

B. Saving a file from your computer to the cloud storage

C. Copying a file from one folder to another on your computer

D. Viewing a file stored in the cloud without downloading

Solution

1. Step 1: Understand uploading concept

   Uploading means moving or saving a file from your local device to a remote place, like cloud storage.

2. Step 2: Apply to AWS S3 context

   In AWS S3, uploading an object means saving your local file into an S3 bucket in the cloud.

3. Final Answer:

   Saving a file from your computer to the cloud storage -> Option B

4. Quick Check:

   Uploading = Save local file to cloud [OK]

Hint: Uploading means sending files from your PC to cloud storage [OK]

Common Mistakes:

• Confusing uploading with downloading
• Thinking uploading deletes files
• Mixing local file moves with cloud uploads

2. Which AWS CLI command correctly uploads a file named photo.jpg to a bucket called mybucket?

easy

A. aws s3 get photo.jpg s3://mybucket/

B. aws s3 download photo.jpg s3://mybucket/

C. aws s3 cp photo.jpg s3://mybucket/

D. aws s3 remove photo.jpg s3://mybucket/

Solution

1. Step 1: Identify correct AWS CLI upload command

   The command to upload files to S3 is aws s3 cp followed by the local file and the bucket path.

2. Step 2: Match command with given file and bucket

   Using aws s3 cp photo.jpg s3://mybucket/ uploads the file photo.jpg to the bucket mybucket.

3. Final Answer:

   aws s3 cp photo.jpg s3://mybucket/ -> Option C

4. Quick Check:

   Upload command = aws s3 cp [OK]

Hint: Use 'aws s3 cp' to copy files to S3 bucket [OK]

Common Mistakes:

• Using 'download' instead of 'cp' for upload
• Confusing 'get' with upload command
• Using 'remove' which deletes files

3. What will be the result of this AWS CLI command?
aws s3 cp s3://mybucket/report.pdf ./

medium

A. Downloads report.pdf from the bucket to current folder

B. Uploads report.pdf from local to the bucket

C. Deletes report.pdf from the bucket

D. Lists all files in the bucket

Solution

1. Step 1: Understand the command structure

   The command aws s3 cp copies files. The source is s3://mybucket/report.pdf and destination is ./ (current folder).

2. Step 2: Determine direction of copy

   Since source is S3 and destination is local, the file is downloaded from the bucket to the local folder.

3. Final Answer:

   Downloads report.pdf from the bucket to current folder -> Option A

4. Quick Check:

   Source S3 to local = download [OK]

Hint: Source path starting with s3:// means download to local [OK]

Common Mistakes:

• Thinking 'cp' always uploads
• Confusing source and destination order
• Assuming it deletes files

4. You run this command to download a file but get an error:
aws s3 cp s3://mybucket/data.csv ./
What is the most likely cause?

medium

A. You forgot to add --recursive flag

B. You used the wrong command; should be aws s3 upload

C. The local folder ./ does not exist

D. The file data.csv does not exist in the bucket

Solution

1. Step 1: Analyze the error context

   The command is correct for downloading a single file. An error usually means the file is missing or inaccessible.

2. Step 2: Check common causes

   If the file data.csv is not in the bucket, the command fails. The local folder ./ always exists as current directory, and --recursive is not needed for single files.

3. Final Answer:

   The file data.csv does not exist in the bucket -> Option D

4. Quick Check:

   Missing file in bucket causes download error [OK]

Hint: Check if file exists in bucket before downloading [OK]

Common Mistakes:

• Using wrong command for download
• Assuming local folder missing causes error
• Adding unnecessary flags

5. You want to upload all files from your local folder photos/ to the S3 bucket mybucket preserving folder structure. Which command should you use?

hard

A. aws s3 sync photos/ s3://mybucket/

B. aws s3 cp photos/ s3://mybucket/

C. aws s3 cp photos/ s3://mybucket/ --no-recursive

D. aws s3 mv photos/ s3://mybucket/ --recursive

Solution

1. Step 1: Understand folder upload options

   To upload multiple files preserving folder structure, aws s3 sync is preferred as it copies all files and folders efficiently.

2. Step 2: Compare commands

   aws s3 cp --recursive can copy folders but sync is better for syncing changes and preserving structure. mv moves files (deletes local), which may not be desired.

3. Final Answer:

   aws s3 sync photos/ s3://mybucket/ -> Option A

4. Quick Check:

   Use 'sync' to upload folders preserving structure [OK]

Hint: Use 'aws s3 sync' for folder uploads preserving structure [OK]

Common Mistakes:

• Using 'cp' without --recursive for folders
• Using 'mv' which deletes local files
• Forgetting to preserve folder structure