can1357/oh-my-pi · error · CatError

No such device or address

Error message

No such device or address

What it means

`CatError::NoSuchDeviceOrAddress` (unix-only) reports ENXIO — the path refers to a device special file but no device exists at that address, or the device cannot be opened in the requested mode. It is raised when opening/reading a character/block device yields this specific errno, letting `cat` print coreutils' exact wording instead of Rust's raw error string.

Source

Thrown at crates/pi-builtins/src/cat.rs:81

		writer.write_all(self.to_str())
	}
}

#[derive(Error, Debug)]
enum CatError {
	/// Wrapper around `io::Error`.
	#[error("{}", strip_errno(.0))]
	Io(io::Error),
	/// The downstream reader closed its pipe; this ends the copy quietly.
	#[error("broken pipe")]
	BrokenPipe,
	/// Unknown file type; it is not a regular file, socket, or known device.
	#[error("unknown filetype: {ft_debug}")]
	UnknownFiletype { ft_debug: String },
	#[error("Is a directory")]
	IsDirectory,
	#[cfg(unix)]
	#[error("No such device or address")]
	NoSuchDeviceOrAddress,
	#[error("Too many levels of symbolic links")]
	TooManySymlinks,
}

impl From<io::Error> for CatError {
	fn from(error: io::Error) -> Self {
		if error.kind() == ErrorKind::BrokenPipe {
			Self::BrokenPipe
		} else {
			Self::Io(error)
		}
	}
}

fn strip_errno(error: &io::Error) -> String {
	let mut message = error.to_string();
	if let Some(position) = message.find(" (os error ") {

View on GitHub (pinned to 9690622007)

Solutions

1. Verify the device node is valid and its driver is loaded (`ls -l /dev/...`, `lsof`, kernel module list).
2. In containers, mount/prepare the required device (e.g. --device with docker) before reading it.
3. Don't cat device special files expecting data; use the appropriate tool (dd, socat) if you need device I/O.

Example fix

// before
$ cat /dev/video0
cat: /dev/video0: No such device or address
// after
$ ls /dev/video*    # ensure driver loaded / device attached
$ dd if=/dev/video0 bs=1 count=1   # or use a v4l tool instead

// shell: confirm the device node is present and readable before cat-ing
DEV=/dev/video0
if [ ! -c "$DEV" ]; then echo "no such device node: $DEV" >&2; exit 1; fi
if ! dd if="$DEV" of=/dev/null count=1 2>/dev/null; then
  echo "device not accessible: $DEV" >&2; exit 1
fi

// Rust caller: match the specific errno variant
if matches!(err, CatError::NoSuchDeviceOrAddress) {
    eprintln!("device not available at that address");
}

// shell: degrade gracefully when a device is unavailable
if ! cat -- "$DEV" 2>/dev/null; then
  echo "warning: $DEV unavailable, continuing" >&2
fi

When it happens

Trigger: `cat /dev/ttyX` where the tty has no controlling process; opening a device node whose driver/module is not loaded; `cat` on a unix socket path or special file that resolves to no live device (ENXIO from open/read).

Common situations: Scripts referencing /dev entries that only exist conditionally (missing kernel module, container without the device mounted); cat-ing device nodes that require exclusive or special open semantics; stale /dev paths after hardware changes.

Related errors

• unknown function: {0}
• unknown key binding function: {0}
• unimplemented: {0}
• I/O error occurred
• transparent (brush_parser::BindingParseError)

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/96eb842aac16d87f. Report an issue: GitHub.