ECHO Command

The ECHO command disables and enables the echoing, or displaying on the screen of characters entered at the keyboard. If echoing is disabled, input will not appear on the terminal screen as it is typed. Echoing is enabled by default.

Format

Parameter(s)

These options are used to set echoing explicitly, regardless of its current state. Simply entering ECHO toggles the current status of echoing on or off.

Description

For certain applications a user might want to suppress echoing at the terminal screen. For example, to promote system security, user passwords are not generally echoed.

System messages and output continue to be displayed normally even when echoing is disabled.

Output from a process can be suppressed with the P command.

Suppressing Echoing on a Terminal Screen

The following example shows how ECHO suppresses terminal input on the screen. First, ECHO is entered, disabling the display of input. At the next TCL prompt, the TCL Stacker command .L3 was entered, as can be seen from the following output. The command itself, however, does not appear. At the third TCL prompt the ECHO command was entered again, enabling ECHO the display of input. The command ECHO does not appear, because the command does not take effect until ENTER is pressed. But now that echoing is re-enabled, when the .L command is entered again, .L is echoed to the screen.