Read stderr from a child process

When you spawn a child process with Bun.spawn(), it inherits the stderr of the spawning process. To read and handle stderr instead, set the stderr option to "pipe".

const proc = Bun.spawn(["echo", "hello"], {
  stderr: "pipe",
});

proc.stderr; // => ReadableStream

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To read stderr until the child process exits, use .text().

const proc = Bun.spawn(["echo", "hello"], {
  stderr: "pipe",
});

const errors: string = await proc.stderr.text();
if (errors) {
  // handle errors
}

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See Child processes.