Info Node: (fileutils.info)Conditional Executability
(fileutils.info)Conditional Executability
Conditional Executability
-------------------------
There is one more special type of symbolic permission: if you use
`X' instead of `x', execute permission is affected only if the file
already had execute permission or is a directory. It affects
directories' execute permission even if they did not initially have any
execute permissions set.
For example, this mode:
a+X
gives all users permission to execute files (or search directories) if
anyone could before.