I wrote a batch file that examines the output of dir ???????.txt
and echoes only the files that have 7 characters (11, including .txt).
@ECHO OFF
REM --- Call Subroutine for all files of Len 1 - 7 characters ---
For /f "delims=*" %%a in ('dir "c:\???????.txt" /b') do Call :CheckLen %%~nxa
REM --- End Batchfile ---
Goto :eof
:CheckLen
REM --- Place Filename in Variable FNAME ---
Set FName=%*
REM --- IF Valiable FName <> First 10 characters of FName, FName has ---
REM --- 11 Characters (7 + .txt). Echo Output ---
if NOT "%FName%"=="%FName:~0,10%" Echo %FName%
Note: In line 'dir "c:\???????.txt" /b'
,add /s
if you want also to search the subdirectories of C:. This will probably take a long time without output.