[Reverence]

i mean what i've seen is:

texttexttext

is inserted into the three files we've included in bracket (a, b, c) so i would assume that "texttexttext" is defined into %%a, so that's mean that 'a' variable in this case is not the same 'a' as the first variable that we created (which contains "text.txt") ? and the value of %%a is defined within do block right?

Code:

do ( echo texttexttext>%%a )

No. Texttexttext is WRITTEN into the file that is defined by "%%a".