1GENERAL: echo - variable to control the echoing of commands

"echo" is a variable that determines which commands are echoed, i.e. copied
to standard output before execution. The possible settings are:

NULL  (or not set at all) In macros, commands that are not built into 
      the command interpreter are echoed; interactively, commands are
      not echoed.
on    Commands that are not built into the command interpreter are 
      echoed regardless of whether they occur in macros or interactively.
full  All commands are echoed, and the corresponding line numbers in
      macros are given.
off   Commands are not echoed.

Labels are not included in the echo; variable substitutions are included
in the echo. Statements that are preceded by "@" are only echoed if the
variable "echo" has the value "full".