CLI output formats (json, table, text) in AWS - Mini Project: Build & Apply

AWS CLI Output Formats (json, table, text)

📖 Scenario: You are managing AWS resources using the AWS Command Line Interface (CLI). AWS CLI lets you choose how the output looks, which helps you read or use the data better.Imagine you want to see a list of your S3 buckets. You can ask AWS CLI to show this list in different ways: as JSON data, as a simple table, or as plain text.

🎯 Goal: Learn how to use AWS CLI to get the same information in three different output formats: JSON, table, and text.You will practice commands that show your S3 buckets in these formats.

📋 What You'll Learn

Use AWS CLI commands to list S3 buckets

Use the --output option to change output format

Show output in JSON format

Show output in table format

Show output in text format

💡 Why This Matters

🌍 Real World

AWS CLI output formats help cloud engineers and developers quickly read or process AWS resource data in the way that suits their task best.

💼 Career

Knowing how to change AWS CLI output formats is a basic skill for cloud administrators, DevOps engineers, and developers working with AWS.

1

List S3 buckets in JSON format

Write the AWS CLI command to list all S3 buckets using the aws s3api list-buckets command with the output format set to json using the --output option.

AWS

# Type the AWS CLI command to list S3 buckets in JSON format
# Your code here

Hint

Use --output json to get the output in JSON format.

2

List S3 buckets in table format

Write the AWS CLI command to list all S3 buckets using the aws s3api list-buckets command with the output format set to table using the --output option.

AWS

aws s3api list-buckets --output json
# Change the output format to table
# Your code here

Hint

Use --output table to get the output in a table format.

3

List S3 buckets in text format

Write the AWS CLI command to list all S3 buckets using the aws s3api list-buckets command with the output format set to text using the --output option.

AWS

aws s3api list-buckets --output table
# Change the output format to text
# Your code here

Hint

Use --output text to get the output in plain text format.

4

Set default output format in AWS CLI config

Write the AWS CLI command to set the default output format to json using the aws configure set command.

AWS

aws s3api list-buckets --output text
# Set default output format to json
# Your code here

Hint

Use aws configure set default.output json to set the default output format.

Practice

1. What does the --output json option do when used with an AWS CLI command?

easy

A. It displays the output as a simple text list.

B. It saves the output directly to a file.

C. It shows the output in a table format for easy reading.

D. It formats the command output as structured JSON data.

Solution

1. Step 1: Understand the purpose of --output option

   The --output option controls how AWS CLI displays command results.

2. Step 2: Identify what 'json' output means

   Choosing json formats the output as structured JSON, which is machine-readable and easy to parse.

3. Final Answer:

   It formats the command output as structured JSON data. -> Option D

4. Quick Check:

   --output json = structured JSON output [OK]

Hint: JSON output is structured and good for programs [OK]

Common Mistakes:

• Confusing JSON with table or text output
• Thinking JSON saves output to a file automatically
• Assuming JSON is for human reading only

2. Which of the following is the correct syntax to display AWS CLI command output in a table format?

easy

A. aws ec2 describe-instances --output table

B. aws s3 ls --output text

C. aws iam list-users --format table

D. aws lambda list-functions --output json

Solution

1. Step 1: Identify the correct option for table output

   The AWS CLI uses --output table to format output as a table.

2. Step 2: Check each option's syntax

   aws ec2 describe-instances --output table uses --output table correctly. aws iam list-users --format table uses --format which is invalid. Options B and D use other formats.

3. Final Answer:

   aws ec2 describe-instances --output table -> Option A

4. Quick Check:

   Table output uses --output table [OK]

Hint: Use --output table for readable tables [OK]

Common Mistakes:

• Using --format instead of --output
• Confusing text and table output options
• Missing the --output flag entirely

3. Given the command aws s3api list-buckets --output text, what is the expected format of the output?

medium

A. A JSON object with bucket details.

B. Plain text with bucket names and details separated by tabs.

C. An XML formatted list of buckets.

D. A human-friendly table with borders.

Solution

1. Step 1: Understand the --output text format

   The text output format produces plain text with fields separated by tabs, suitable for scripts.

2. Step 2: Match output format to options

   Plain text with bucket names and details separated by tabs. describes plain text with tab-separated values, which matches --output text. JSON and XML are not text formats, and table includes borders.

3. Final Answer:

   Plain text with bucket names and details separated by tabs. -> Option B

4. Quick Check:

   --output text = tab-separated plain text [OK]

Hint: Text output is tab-separated plain text [OK]

Common Mistakes:

• Confusing text output with JSON or table
• Expecting borders or formatting in text output
• Assuming XML output is default

4. You run aws ec2 describe-instances --output tab but get an error. What is the likely cause?

medium

A. The AWS CLI version does not support output formatting.

B. The command requires additional parameters to run.

C. The correct output format is 'table', not 'tab'.

D. The 'tab' output format is deprecated and replaced by 'text'.

Solution

1. Step 1: Identify the valid output formats

   AWS CLI supports 'json', 'table', and 'text' as output formats. 'tab' is not valid.

2. Step 2: Analyze the error cause

   Using 'tab' instead of 'table' causes a syntax error because 'tab' is not recognized.

3. Final Answer:

   The correct output format is 'table', not 'tab'. -> Option C

4. Quick Check:

   Valid formats: json, table, text [OK]

Hint: Use 'table' not 'tab' for table output [OK]

Common Mistakes:

• Typing 'tab' instead of 'table'
• Assuming 'tab' is a valid alias
• Ignoring error messages about output format

5. You want to write a script that extracts only the bucket names from aws s3api list-buckets. Which output format should you choose to easily parse the bucket names in a shell script?

hard

A. Use --output text for simple tab-separated values.

B. Use --output table and extract names from the table.

C. Use --output json and parse with a JSON tool.

D. Use --output xml for structured parsing.

Solution

1. Step 1: Consider parsing ease in shell scripts

   Shell scripts handle plain text easily, especially tab-separated values.

2. Step 2: Match output format to parsing needs

   --output text produces simple tab-separated output, ideal for shell tools like cut or awk. JSON requires extra tools, table is formatted for humans, XML is unsupported.

3. Final Answer:

   Use --output text for simple tab-separated values. -> Option A

4. Quick Check:

   Text output is easiest for shell parsing [OK]

Hint: Text output is easiest for shell scripts [OK]

Common Mistakes:

• Choosing JSON without JSON parsing tools
• Trying to parse table output in scripts
• Assuming XML output is supported