`echoifempty` is a utility that echoes the value of `<a>` if `<str>` is empty, echoes the value of `<b>` otherwise.

```text
Usage:
    ops -echoifempty <str> <a> <b>
```

## Example

```bash
  ops -echoifempty "not empty string" "string is empty" "string is not empty"
```