BAT file (YYYY-MM-DD.log)
FOR /F %%Z in ('dir *.txt /B /OD /TC') do FOR /F "tokens=1,2,3,4,5,6* delims=.:/ " %%a in (%%Z) do @echo %%a.%%b.%%c/%%d:%%e:%%f %%g >>%%c-%%b-%%a.log
or {YYYY-MM-DD.UserID} format
FOR /F %%Z in ('dir *.txt /B /OD /TC') do FOR /F "tokens=1,2,3,4,5,6,7* delims=.:/ " %%a in (%%Z) do @echo %%a.%%b.%%c/%%d:%%e:%%f %%g/%%h >>%%c-%%b-%%a.%%g
you can sort by name or ext in file-browser