@EXEC

@EXEC[[@]command]:  Execute the command and return the numeric exit code. 
 The command can be an alias, internal command, external command, or .BTM 
file, .BAT, or .CMD file. 

@EXEC is primarily intended for running a program from within the PROMPT. 
 It is a "back door" entry into command processing and should be used with 
extreme caution.  Incorrect or recursive use of @EXEC may hang your 
system. 

By default, @EXEC returns the result code from the command; if you preface 
the command name with an '@' then @EXEC will return an empty string.