Use Claude as a Unix Utility

Add Claude to a Validation Workflow

Suppose you want to use Claude Code as a linter or code reviewer.

Add Claude to your build scripts:

// package.json
{
    ...
    "scripts": {
        ...
        "lint:claude": "claude -p 'you are a linter. please look at the changes vs. main and report any issues related to typos. report the filename and line number on one line, and a description of the issue on the second line. do not return any other text.'"
    }
}

Tips:

Use Claude in your CI/CD pipeline for automated code review
Customize prompts to check for project-specific issues
Consider creating multiple scripts for different types of validation

Pipe Input, Pipe Output

Suppose you want to pipe data through Claude and get it back in a structured format.

Pipe data through Claude:

cat build-error.txt | claude -p 'concisely explain the root cause of this build error' > output.txt

Tips:

Use pipes to integrate Claude into existing shell scripts
Combine with other Unix tools for powerful workflows
Consider using --output-format for structured output

Control Output Format

Suppose you need Claude to output in a specific format, especially when integrating Claude Code into scripts or other tools.

Use Text Format (Default)

cat data.txt | claude -p 'summarize this data' --output-format text > summary.txt

This outputs only Claude’s plain text response (the default behavior).

Use JSON Format

cat code.py | claude -p 'analyze this code for bugs' --output-format json > analysis.json

This outputs a JSON array of messages including metadata such as cost and duration.

Use Stream-JSON Format

cat log.txt | claude -p 'parse this log file for errors' --output-format stream-json

This outputs a series of JSON objects in real time as Claude processes the request. Each message is valid JSON, but the complete output is not valid JSON if concatenated.

Tips:

Use --output-format text for simple integrations that only need Claude’s response
Use --output-format json when you need the full conversation log
Use --output-format stream-json for real-time output of each conversation turn

Run Parallel Sessions Custom Slash Commands