Function Reference
— Command: echo options

Control whether commands are displayed as they are executed. Valid options are:

on
Enable echoing of commands as they are executed in script files.
off
Disable echoing of commands as they are executed in script files.
on all
Enable echoing of commands as they are executed in script files and functions.
off all
Disable echoing of commands as they are executed in script files and functions.

If invoked without any arguments, echo toggles the current echo state.