@EXECSTR

@EXECSTR[command]:  Runs the specified command and returns the first line 
written to STDOUT by that command. 

@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. 

@EXECSTR is useful for retrieving a result from an external utility -- for 
example, if you have an external utility called NETTIME.EXE which 
retrieves the time of day from your network server and writes it to 
standard output, you could save it in an environment variable using a 
command like this: 

        [c:\] set server_time=%@execstr[d:\path\nettime.exe]

If the same utility returned a result properly formatted for the TIME 
command you could also use it to set the time on your system: 

        [c:\] time %@execstr[d:\path\nettime.exe]