On Fri, 23 Feb 2018 02:51:52 -0500 (EST) "Robert P. J. Day" <rpjday [ at ] crashcourse [ dot ] ca> wrote: > i can't believe i've never noticed the 'X' (upper case) permission > setting for the chmod command, explained thusly in the man page: > > "The letters rwxXst select file mode bits for the affected users: read > (r), write (w), execute (or search for directories) (x), > execute/search only if the file is a directory or already has execute > permission for some user (X), set user or group ID on execution (s), > restricted deletion flag or sticky bit (t)..." > what is the rationale for that particular setting? what problem is > it trying to solve? i'm just a bit puzzled. Let's say you have an entire directory tree that's only user-readable. You want to make it group- and other-readable and also make the directories therein group- and other-executable. You'd use: chmod -R og+rX /root/of/tree This turns on execute permissions for directories (and any files that are executable), but not for normal non-executable files. Regards, Dianne.