CLI output formats (json, table, text) in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

AWS CLI Output Format: JSON vs Table

You run the AWS CLI command aws s3 ls with the output format set to json and then with table. What is the main difference in the output you will see?

A JSON output shows structured data with keys and values, while table output shows a formatted, human-readable table.

B JSON output shows colored text, table output shows plain text without colors.

C JSON output is only for errors, table output shows successful command results.

D JSON output is a plain text list of filenames, table output shows JSON objects.

💡 Hint

Think about how JSON and tables represent data differently.

JSON output provides structured data with keys and values, useful for automation. Table output formats the data into a readable table for humans.

🧠 Conceptual

intermediate

Default AWS CLI Output Format

What is the default output format of the AWS CLI if you do not specify any output option?

A table

B json

C text

D yaml

💡 Hint

Check the AWS CLI documentation for default settings.

The AWS CLI defaults to JSON output format unless changed by configuration or command option.

❓ Configuration

advanced

Changing AWS CLI Output Format Permanently

You want to change the AWS CLI output format to table permanently for your user. Which command correctly updates your AWS CLI configuration?

A aws configure --output table

B aws configure output table

C aws set output table

D aws configure set output table

💡 Hint

Look at the syntax for the aws configure set command.

The correct syntax to set output format permanently is aws configure set output table.

❓ service_behavior

advanced

AWS CLI Output Format: Text

When using the AWS CLI with output format set to text, what is the typical structure of the output?

A Plain text with tab-separated columns and no JSON structure.

B JSON objects with indentation and line breaks.

C A formatted table with borders and headers.

D XML formatted output with tags.

💡 Hint

Think about how text output differs from JSON and table.

Text output is plain text with tab-separated columns, easy to read but not structured like JSON.

✅ Best Practice

expert

Choosing AWS CLI Output Format for Automation

You are writing a script that processes AWS CLI command output to automate resource management. Which output format should you choose to make parsing easiest and most reliable?

A text

B table

C json

D yaml

💡 Hint

Consider which format is easiest for machines to parse.

JSON is structured and widely supported for parsing in scripts, making it the best choice for automation.

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