name[1].ext
name[2].extname[3].extname[4].extname[5].ext
...
name[2].extname[3].extname[4].extname[5].ext
...
So what do you have to do? You can use a simple script like this:
@echo off for /f "tokens=1,2,3 delims=[]" %%a in ('dir /b *[1].*') do ren %%a[%%b]%%c %%a%%c
Hope you'll find it useful.