I was saying that Accept Headers or "format negotiation" concepts that are typically used in client-server communications are a bit overkill for command line to

I was saying that Accept Headers or "format negotiation" concepts that are typically used in client-server communications are a bit overkill for command line tools and shell pipelines. I agree that human-readable text formats should be the default output formats for command line tools, but that easy-to-parse structured text output formats should be easy to specify with either environment variables or command line flags. If I am writing a script and I am using tools that support a given structured output format and use environment variables or command line flags for output configuration it could work something like this: #!/bin/env script-interpreter export PREFERRED_OUTPUT_FORMAT="JSON" query-cli-tool | filter-cli-tool --output-format=json | combinator-cli-tool --input-format=json | pretty-formatter-tool > output_file This would mean that the command line tools default to human-readable formats, but can still generate JSON or some other structured text format when configured to do so.