Echo

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

off Commands are not echoed. NULL (or not set at all) In macros, all commands except those built into

       the command line interpreter are echoed; interactive 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.

large Same as "on", except that the echo is surrounded by blank lines. full All commands are echoed, and the corresponding line numbers in

       macros are given.

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