How to use unison to sync files in ext4 filesystem with FAT filesystem? (permission bit)

My machine is linux ext4. I have an external hard drive with FAT. I can syn most of the files without any problem. However, there is always a few files having permission problems.

I tried to use unison -fat to specify the sync policy. However, unison does not seem to take my command. Here is what I tried:

My profile.pcf specify the path: (from home to media)

root = /home/allen/allen
root = /media/portable/allen

Then I type this:

unison work -fat perm=0

In both of the commands, unison treats work as a directory rather than a profile. Please give some hints.

Thank you!

Solution 1:

To be able to use a profile work you must create a file ~/.unison/work.prf. According to the documentation you just have to add a line fat = true to the profile in order to make synchronization with FAT file systems work.