in CMD:
H:\>hellohtml.bat

H:\>SETLOCAL EnableDelayedExpansion

H:\>Set _html=<title>Hello world </title>

H:\>Echo !_html!
<title>Hello world </title>

in TCC:
[H:\]hellohtml.bat
SETLOCAL EnableDelayedExpansion
Set _html=^<title^>Hello world ^</title^>
Echo <title>Hello world </title>
TCC: (Sys) H:\hellohtml.bat [3]  The system cannot find the file specified.
 ""

[H:\]