httpd-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Gil Dawson <...@GilDawson.com>
Subject Re: [users@httpd] Apache & Unix
Date Mon, 29 Dec 2014 20:09:43 GMT
Excellent response, Mark!  

Exactly what I needed.

Thank you.

--Gil

On Dec 29, 2014, at 11:40 AM, Mark Montague wrote:

> On 2014-12-29 14:01, Gil Dawson wrote:
>> I'm having a little problem understanding the Unix terminology.
> 
> You may find Chapter 2 of the freely available book "The Linux Command Line" ( http://linuxcommand.org/tlcl.php
) to be helpful.      Although this book is about Linux, not MacOS X, both are based on Unix.
> 
>> This paragraph has me stumped.
>> 
>> '...if the filenames ... begin with "/"' 
>> --
>>               I cannot imagine how a filename could begin with "/".  
>> Does the author possibly mean pathname?  
>> A pathname might begin with either a "/" or a "~", would it not?
> 
> Configuration and log files are files, whereas pathnames can point to anything.  So although
it may be confusing, I think that "filename" is the correct terminology here.  The filename
may be just the name of a file without any directory component, or it may     include a relative
directory component or an absolute directory component.  Examples:
> 
> Simple filename:   extra-stuff.conf (look for the file "extra-stuff.conf" inside the
current directory)
> 
> With relative directory:  my-stuff/extra-stuff.conf  (look for the file "extra-stuff.conf"
inside the directory "my-stuff" which in turn is in the current directory").  Note that this
is the same as ./my-stuff/extra-stuff.conf
> 
> Another example with a relative directory: ../../another-place/extra-stuff.conf (go up
two directory levels from the current directory, then into the directory "another-place" and
then the file is extra-stuff.conf).
> 
> Absolute directory component:  /private/etc/apache2/extra-stuff.conf
> 
>> 
>> "If the filenames do *not* begin with "/", ... "/private/var/log/apache2/foo_log"
>> -- This is an example of a filename that does not begin with "/", right?
>> I don't get it.  I see "/" at the beginning of everything.
>> What would be an example of a filename that does begin with "/"?
> 
> /private/var/log/apache2/foo_log" *does* begin with "/".  You're trying to make too much
of a distinction between pathnames and filenames.
> 
>> "/usr//private/..."
>> -- What is the meaning of "//" in this context?
> 
> It has no meaning, extra slashes between directory components are ignored.  This lets
scripts and other programs construct filenames without having to detect and remove extraneous
slashes; if a script always adds a slash, it will be there when needed and won't cause problems
if it is not needed.  The following are all equivalent:
> 
> /usr/private
> /usr//private
> /usr/private/
> /////usr/////private/////
> 
> For more reading, see http://teaching.idallen.com/cst8207/12f/notes/160_pathnames.html
> 
> -- 
>   Mark Montague
>   mark@catseye.org


Mime
View raw message