CODE: [Copy to clipboard]
@echo off&setlocal ENABLEDELAYEDEXPANSION
for %%a in (*.txt) do call:mytest "%%a"
:mytest
set a=abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
set /a a_=(%random%+62)%%62
set /a b_=(%random%+62)%%62
set /a c_=(%random%+62)%%62
set /a d_=(%random%+62)%%62
set /a e_=(%random%+62)%%62
set /a f_=(%random%+62)%%62
echo rename %1 !a:~%a_%,1!!a:~%b_%,1!!a:~%c_%,1!!a:~%d_%,1!!a:~%e_%,1!!a:~%f_%,1!.txt
rename %1 !a:~%a_%,1!!a:~%b_%,1!!a:~%c_%,1!!a:~%d_%,1!!a:~%e_%,1!!a:~%f_%,1!.txt
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