A long time ago I made a command-line based mass renaming tool called nmrename (Noneus’ Mass Renming Tool). Noneus was my old nickname. I use this program all the time and think it might be helpful to others. I made the 1.0 release on GiHub.
Here is the help-text:
Help for nmrename 1.0
USAGE:
C:\Apps\nmrename\nmrename.exe: [FILES ...] [COMMAND ...] ...
Positions are indexes for the filename. Start an
index with "-", if you want to start index counting
from the end of the filename.
COMMANDS:
-h --help : Print this help output.
-d : Rename folderstructure too. Be careful with "/"'s!
-f : Don't ask. Just rename.
-l #1 : Load rename target paths from file #1 line by line.
-cc : Convert filename to camel case.
-cl : Convert filename to lower case.
-cu : Convert filename to upper case.
-exif #1 : Rename from EXIF-Data with a pattern. (e.g. %Y.%M.%D_%h:%m:%s_%O%e)
Pattern Elements:
%Y: year (e.g. 2012)
%M: month (e.g. 06)
%D: day (e.g. 09)
%h: hour (e.g. 14)
%m: minute (e.g. 40)
%s: second (e.g. 09)
%o: complete original filename
%e: extension (e.g. .jpg)
%O: filename without extension
-fi #1 #2 : Insert filecount line from #2 at position #1.
-fieldc #1 #2 #3 : Change field #2 with field #3 delimited by #1.
-fieldd #1 #2 : Remove field #2 delimited by #1.
-fn #1 : Insert filecount line from #1.
-pd #1 #2 : Delete from position #1 to position #2.
-ps #1 #2 : Set character at position #1 to character #2.
-pyr #1 #2 : Replace the pattern "#1" with "#2" with python regex-interpreter.
( https://docs.python.org/library/re.html#re.sub )
-sd #1 : Remove string #1 from all filenames.
-si #1 #2 : Insert string #2 at position #1.
-sr #1 #2 : Replace string #1 with string #2.
-tag #1 : Rename from audio tags with a pattern. (e.g. "%a - %A - %t - %y%e")
Pattern Elements:
%a: artist
%A: album
%AA: albumartist
%t: title
%y: year
%tn: track-number
%Tn: total-tracks
%e: file extension