set text = Hello world

@ECHO OFF

::Edit string one with 30 char limit. String has 40 Chars.
SET String=0123456789012345678901234567890123456789
SET Result=%String:~0,30%
ECHO %Result%...

::Edit string one with 30 char limit. String has 90 Chars.
SET String=012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
SET Result=%String:~0,30%
ECHO %Result%...

::Edit string one with 30 char limit. String has 6 Chars.
SET String=0123456
SET Result=%String:~0,30%
ECHO %Result%...

PAUSE
GOTO :EOF