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.