In Mac OS X Snow Leopard, how can one file's permissions be matched to another?

Question

I need to make the permissions of a file exactly match the permissions of another file in OS X 10.6.

I don't see 'getfacl' or 'setfacl' as suggested in some other posts for Linux. And, it doesn't look like chown/chmod have a --reference option in Snow Leopard.

What is the equivalent on the Mac?

Answer 1

Use ls -le to see any acls a file has associated with it.

Use chmod to change or remove the acls. There are plenty of examples toward the end of the chmod man page to guide you.

Mac OS has a separate set of file access flags, apparently inherited from the BSDs. You can see those with ls -lO (that's dash ell oh) and modify them with chflags.

Answer 2

OK, so for a straight ACL copy, I can't see a single command. However, you can put this in a script or function:

ls -le source | sed -En '/^ [[:digit:]]+: / { s/^ [[:digit:]]+: //; p; }' | chmod -E dest

eg.

function copyacl()
{
  ls -le "$1" \
    | sed -En '/^ [[:digit:]]+: / { s/^ [[:digit:]]+: //; p; }' \
    | chmod -E "$2"
}

$ copyacl sourcefile destfile

I feel like that sed script could be improved, but it seems to do the job.

Answer 3

Not sure if you are ask about standard UNIX permissions or for ACL's. Many versions of chmod have a --reference option to take the permissions of another file:

chmod --reference=~/backup/file ~/newfile

But you'll need to check the options for chmod on your Mac:

chmod --help