What does the @ mean on the output of "ls" on OS X' terminal?

"From the ls(1) man page on Mac OS 10.6.1:

If the file or directory has extended attributes, the permissions field printed by the -l option is followed by a '@' character. Otherwise, if the file or directory has extended security information (such as an access control list), the permissions field printed by the -l option is followed by a '+' character.

From the available options list:

-@ Display extended attribute keys and sizes in long (-l) output.

-e Print the Access Control List (ACL) associated with the file, if present, in long (-l) output.

These will let you see the value of those extended options. FWIW, ACL info can be set using the same chmod(1) utility you are probably already aware of. :-)

There doesn't appear to be an easy way from the command line to do anything with extended attributes."

"The ""@"" means that the file has ""extended attributes"" associated with it.

If you do ""ls -@ -l"", you can see what attributes there are for each file. You can also do something like ""xattr -l pgsql.so"" to dump the attributes for a particular file.

Typically they're stuff like old-school FinderInfo, text encoding info, or the ""quarantine"" info that gives you the ""This file was downloaded from the web, are you sure you want to open it?"" warning."

"From the man page of ls:

The Long Format
[…] If the file or directory has extended attributes, the permissions field printed by the -l option is followed by a '@' character. […]"