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Re: [OCLUG-Tech] what the heck is the rationale for 'X' in chmod command?

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.