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Re: suggested feature/patch for ls: -P TYPES, --select-file-type=TYPES
From: |
Moreno Baricevic |
Subject: |
Re: suggested feature/patch for ls: -P TYPES, --select-file-type=TYPES |
Date: |
16 Dec 2005 13:38:37 +0100 |
On Fri, 2005-12-16 at 09:25, Paul Eggert wrote:
> I don't recall the earlier thread, but my kneejerk reaction is that
> this sort of thing can be done fairly easily with commands like
> "ls -l | grep '^d'". No doubt I'm missing something...
Yes, it's exactly what I wrote on my first mail about ls, find, test.
My point is that on a populated directory (e.g. /dev on 2.4), filtering
file types inside ls is faster than doing it externally by parsing a
huge output.
If d_type is supported by the file system, the additional cost for 'ls
-P' is a stat() on directories and symlinks (this allows -R, -L and the
like); otherwise (no d_type), a stat() is needed for every file (exactly
as in both "ls -l" and "find -type") but the output is what you're
looking for without further filtering.
If -P is not used, there's no cost at all for ls (other than 2 or 3
if(0)...).
Moreno