Change Title on MP4 and M4V files

[mattbastin]

Hi I'm trying to change the TAG 'Title' to a new setting on Linux command line thus
exiftool -Title='New Name' Filename
but nothing happens. Its either taking a very long time or its hung with no error messages. I mean surely if its write protected the utility would return that, wouldn't it?
I have successfully run the utility to return metadata.
Can any one help please.

[Hayo Baan]

How big is the movie file? Before exiftool does anything it will create a copy of the file and that can take a long time...

[mattbastin]

 :)Thanks. I was too impatient. I assumed it would be done in a matter of microseconds.
Consider this post as solved.
Cheers