CLI output formats (json, table, text) in AWS - Step-by-Step Execution

Process Flow - CLI output formats (json, table, text)

User runs AWS CLI command

↓

CLI processes request

↓

Output format option checked

↓

json format

↓

Print JSON

↓

Display output

The AWS CLI command runs, checks the chosen output format, then prints the output in JSON, table, or text format accordingly.

Execution Sample

AWS

aws ec2 describe-instances --output json
aws ec2 describe-instances --output table
aws ec2 describe-instances --output text

Shows how the same AWS CLI command outputs instance info in JSON, table, or text format.

Process Table

Step	Action	Output Format Option	Output Produced
1	Run command	json	JSON structured data with keys and values
2	Run command	table	Table with headers and rows showing instance info
3	Run command	text	Plain text with tab-separated values
4	End	any	Output displayed to user terminal

💡 Output format option determines how the CLI formats and displays the data

Status Tracker

Variable	Start	After json	After table	After text
output_format	none	json	table	text
output_data	none	{"Instances": [...]}	Table rows with headers	Plain text lines

Key Moments - 2 Insights

Why does the output look very different when I change the --output option?

The --output option tells the CLI how to format the data. JSON shows structured data, table shows a readable grid, and text shows simple lines. See execution_table rows 1-3.

Can I parse the output easily if I use table or text formats?

JSON is best for parsing because it is structured. Table and text are for human reading, not easy for scripts. See variable_tracker for output_data differences.

Visual Quiz - 3 Questions

Look at the execution table, what output format produces a grid with headers and rows?

A json

B text

C table

D none

💡 Hint

Check execution_table row 2 under Output Produced

At which step does the CLI print plain text with space-separated values?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

See execution_table row 3 Output Produced column

If you want to automate processing the output, which format should you choose?

A json

B text

C table

D none

💡 Hint

Refer to key_moments about parsing output easily

Concept Snapshot

AWS CLI output formats:
--output json: structured data, easy for scripts
--output table: human-friendly grid with headers
--output text: simple plain text lines
Choose format based on use: json for automation, table/text for reading

Full Transcript

When you run an AWS CLI command, you can choose how the output looks using the --output option. The CLI checks this option and formats the data accordingly. JSON format shows detailed structured data good for scripts. Table format shows a neat grid with headers for easy reading. Text format shows simple lines of text. This choice affects how easy it is to read or parse the output. JSON is best for automation, while table and text are better for humans. The execution table shows the steps from running the command to displaying the output in the chosen 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