Using AWS Command Line Interface[AWS-CLI] for accessing S3 bucket.

Post Date: October 6, 2018
Last Updated: September 27, 2026

Introduction

This guide explains how to install and use the AWS Command Line Interface (AWS CLI) to access and manage an S3 bucket — uploading, downloading, syncing, and managing objects directly from the terminal.

One important update from the original version of this guide: it installed AWS CLI v1 via pip. AWS now recommends AWS CLI v2 — a self-contained installer that doesn’t depend on Python at all, receives ongoing feature updates, and is the version AWS documents by default going forward. The steps below use the current v2 installation method.

Prerequisites

• A Linux, macOS, or Windows machine with terminal access
• An AWS account with an IAM user (or role) that has S3 permissions
• That user’s Access Key ID and Secret Access Key

Architecture

• The AWS CLI is a client — it doesn’t store anything itself, it just sends authenticated API requests to AWS
• Your credentials (Access Key ID + Secret Access Key) authenticate every request
• Each command maps to an underlying S3 API call — aws s3 cp uploads/downloads objects, aws s3 ls lists them, aws s3 sync reconciles a local folder and a bucket

Steps

1. Install AWS CLI v2

Linux:

curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"
unzip awscliv2.zip
sudo ./aws/install

macOS:

curl "https://awscli.amazonaws.com/AWSCLIV2.pkg" -o "AWSCLIV2.pkg"
sudo installer -pkg AWSCLIV2.pkg -target /

Note: The original guide installed AWS CLI v1 via Python and pip (curl get-pip.py, then pip install awscli). That method still technically works, but AWS CLI v2 is now the recommended version — it’s a standalone installer with no Python dependency, and gets ongoing feature updates that v1 generally doesn’t.

2. Verify the Installation

aws --version

You should see output confirming an aws-cli/2.x version.

3. Configure Your Credentials

aws configure

AWS Access Key ID [None]: <your access key>
AWS Secret Access Key [None]: <your secret key>
Default region name [None]: us-east-2
Default output format [None]: json

Security note: Never share or commit these keys anywhere public. If you’re working on a shared or long-lived server, consider using an IAM role instead of static keys where possible.

4. Create a Bucket

aws s3 mb s3://your-bucket-name

5. Upload a File to the Bucket

aws s3 cp ./tests.txt s3://your-bucket-name/folder/

6. List Your Buckets

aws s3 ls

7. Remove a Bucket

aws s3 rb s3://your-bucket-name

If the bucket name doesn’t match exactly, you’ll get a NoSuchBucket error — double-check the name against your aws s3 ls output first.

8. Sync a Local Folder with a Bucket

aws s3 sync ./local-folder s3://your-bucket-name

sync reconciles the contents of a local folder and a bucket (or two buckets), only transferring files that have actually changed — more efficient than re-uploading everything with cp each time.

9. Grant Specific Permissions on Upload (Optional)

cp, mv, and sync support a --grants option to set permissions on objects as they’re uploaded:

aws s3 cp ./file.txt s3://your-bucket-name/ --grants read=uri=http://acs.amazonaws.com/groups/global/AllUsers

Field	Options
Permission	read, readacl, writeacl, full
Grantee_Type	uri, emailaddress, id
Grantee_ID	The actual URI, email, or canonical ID matching the type above

Conclusion

Managing S3 from the command line comes down to installing AWS CLI v2 (rather than the older pip-based v1 method), configuring your credentials once, and using a small set of commands — cp, ls, rb, sync — that map directly to S3 operations. sync in particular is worth knowing well, since it avoids re-uploading unchanged files every time.

Frequently Asked Questions

Is AWS CLI v1 still usable? Yes, but AWS recommends v2 for new setups — it’s actively maintained with new features, while v1 is considered legacy.

Do I need Python installed for AWS CLI v2? No — that’s one of the main differences from v1. AWS CLI v2 is a self-contained installer with no Python dependency.

What’s the difference between cp and sync? cp copies a specific file or folder every time you run it, re-uploading everything. sync compares source and destination first and only transfers what’s actually changed, which is much faster for repeated backups.

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