Does the "watch error opening terminal unknown" mean the command being watched is not executed?

Not necessarily. The `watch` command might still attempt to execute the specified command periodically, but it will fail to display the output interactively or clear the screen properly. You might see the output of the watched command scrolling by, mixed with error messages, or not displayed at all if `watch` exits entirely due to the error. The error primarily affects `watch`'s display capabilities, not the execution of the child command itself.