limit to number of files seen by ls?

[Karl Vogel]

>> On Thursday 23 July 2009 09:41:26 Karl Vogel wrote:

K> Every version of Unix I've ever used had an upper limit on the size of
K> the argument list you could pass to a program, so it won't just be "ls"
K> that's affected here.  That's why I use 1,000 as a rule of thumb for the
K> maximum number of files I put in a directory.

>> On Thu, 23 Jul 2009 10:25:49 -0800, 
>> Mel Flynn <mel.flynn+fbsd.questions at mailing.thruhere.net> said:

M> That arbitrary number works simply because kern.argmax default has been
M> raised somewhere in 6.x (before it was 64kB).

   That arbitrary number has worked very nicely for me for 20 years under
   Solaris, Linux, and several BSD variants.  The main reason I stick
   with 1000 is because directories are read linearly unless you're using
   something like ReiserFS, and I get impatient waiting for more than that
   number of filenames to be sorted when using ls.

M> And MAXNAMLEN in sys/dirent.h is 255.

   That's the maximum length of a single filename in a directory.  Since
   I keep my filenames much shorter, I don't have a problem.

M> Knowing your way around maximum arguments length through xargs as
M> suggested in this thread is much better solution then trying to exercise
M> control over directory sizes, which may or not be under your control in
M> the first place.

   Xargs is very useful, but it's not a substitute for poor design, and
   it's not something you can drop into any existing pipeline without a
   little thought first.

   If your application is trying to create hundreds of thousands or
   millions of files in any one directory, or you're creating lots of
   200-character filenames from hell, then your design is a poor match for
   most varieties of Unix; small directories perform better than enormous
   ones, and lots of commonly-used scripts and programs will fall over
   when handed zillion-file argument lists.

   I'm sure the latest version of <insert-cool-OS-or-filesystem-here>
   fixes all these objections, but not everyone gets to run the latest
   and greatest.  Don't fight your filesystem, and it won't fight you.

-- 
Karl Vogel                      I don't speak for the USAF or my company
Birds of a feather flock together and usually crap on your car.