|Command||basic.echo Statement/BASIC Program
Applicable release versions: AP, R83
|Category||BASIC Program (486)|
|Description||toggles terminal echo on or off.
Typically, terminals attached to the system operate in "echo plex" or "full duplex" mode. Characters typed at a terminal are sent directly to the computer and must be "echoed" back to the terminal before they are displayed on the screen.
"echo off" stops this echoing; that is, characters entered at the terminal are not seen on the screen. However, the characters are sent to the computer and processed as usual; also, any output that originates within the computer is displayed on the screen.
"echo on" returns to the normal mode of full duplex echoing.
An expression that returns zero is equivalent to "echo off". Any other value returned is equivalent to "echo on".
crt "enter password " : echo off input password echo on The password does not display as it is being typed in. Once the password is accepted, "echo" is enabled. secure = userrec<5> echo secure >= 6 Echo is disabled if the "secure" variable is 5 or less. Echo is enabled for 6 or more. echo off ... input string On systems being run in "half duplex", there is no need to echo the character to the terminal display. The terminal has already taken care of display. This proves invaluable when terminals are connected through networks or complicated multiplexing.