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

2018-02-23 Thread Dianne Skoll 
On Fri, 23 Feb 2018 02:51:52 -0500 (EST)
"Robert P. J. Day"  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.

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

2018-02-23 Thread Robert P. J. Day 
On Fri, 23 Feb 2018, Stephen M. Webb wrote:

> On 2018-02-23 02:51 AM, Robert P. J. Day 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.
>
> It lets you fix broken permissions easily.  Imagine a quick "chmod
> -R a+X ." on a home directory in which you unzipped some DOS files
> which lack any POSIX permission to traverse the contained folders,
> because DOS.

  ah, quite so, thanks.

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

2018-02-23 Thread Stephen M. Webb 
On 2018-02-23 02:51 AM, Robert P. J. Day 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.

It lets you fix broken permissions easily.  Imagine a quick "chmod -R a+X ." on 
a home directory in which you unzipped
some DOS files which lack any POSIX permission to traverse the contained 
folders, because DOS.


-- 
Stephen M. Webb  
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