is-redirected

Check if the current custom command's return value is redirected away from display.

Command Type

built-in

Signature

> is-redirected {flags}

Input/output types:

input	output
nothing	bool

Examples

Inside a custom command, report if the call’s return value is redirected (works in if).

> def pipetest [] { if (is-redirected) { "piped" } else { "display" } }; pipetest

Return true when the custom command is piped to another command.

> def pipetest [] { is-redirected }; pipetest | $in
true

Return true when the custom command result is collected into a variable.

> def pipetest [] { is-redirected }; let x = (pipetest); $x
true

Notes

This is a Nushell pipeline-destination check, not an OS TTY check.

Inside a custom command, is-redirected reports if that command’s return value will be piped to another command, collected into a value (let, subexpression), written to a file, or discarded — as opposed to being printed via the normal display path.

Unlike looking at process stdout, this is stable for the entire command body, so it works inside if (...) and let x = (...).

To test if process stdout is a terminal (scripts: ./script | cat), use is-terminal --stdout instead.

Typical pattern for pretty-vs-data custom commands:

def mycmd [] {
  if (is-terminal --stdout) and not (is-redirected) {
    # human-friendly formatting
  } else {
    # structured data for pipelines
  }
}

← input listen is-terminal →