The following explanations & samples show some information about using Mac's extended file attributes (xattr). This is not directly related to CHDK, but to install CHDK from a Mac it may be neccesary to remove the extended attributes - the camera can't handle those files and won't start or run CHDK...

Macintosh computers add an additional character to the a files permissions, mostly on files downloaded from the web. It is a @ sign and means there is an extended atribute assigned to the file. This character can be seen by using the terminal mode (tv screen in applications files) where everything is typed in. Note the @ sign must be removed from both files and folders.

to view files use the ls command

  • to view files with the @ sign use ls -la (parameter -la means: list all)

  • to view the extended atribute text type:
xattr pathname/filename

  • to remove the attribute text type:
xattr -d text to delete pathname/filename

  • to view other options:
xattr -x pathname/filename
  • if the delete function does not work iit sometimes is necessary
to use xattr -w.   to change the form of the attribute