The maximum size for the /E: switch is 32768 bytes. 

Environment Variables:

	%COMPUTERNAME% = "diamond"
	%HOMEDRIVE% = "c:"
	%HOMEPATH% = "\path\to\home"
	%HOMESHARE% = "\\share\home\path"
	%NTVERSION% = ""
	%OS% = ""
	%PROCESSOR_ARCHITECTURE% = "x86" or "MIPS" or "ALPHA"
	%PROCESSOR_LEVEL% for x86: "3" or "4" or "5"
	%USERPROFILE% = %HOMEDRIVE%%HOMEPATH%
	%SYSTEMDRIVE% = "D:"
	%SYSTEMROOT% = "D:\WINNT" = %WINDIR%
	%USERDNSDOMAIN% = "spcsys.com"
	%USERDOMAIN% = "spcsys"
	%USERNAME% = "spc"
	%WINDIR% = ""
	%COMSPEC% = "drive:\windir\system32\cmd.exe /e:2048"


%CMDCMDLINE% expands into the original command line passed to Cmd.exe prior
to any processing by Cmd.exe, provided that there is not already an
environment variable with the name CMDCMDLINE, in which case you will get
its value instead.

%CMDEXTVERSION% expands into the a string representation of the current
value of cmdextversion, provided that there is not already an environment
variable with the name CMDEXTVERSION, in which case you will get its value
instead.