Re: sort - specifying sort fields/keys.

On Tue, Apr 08, 2008 at 11:22:27AM EDT, Bob Proulx wrote:
> cga2000 wrote:
> > I wanted to sort the output of the ls command by filename and with 
> > directories first and regular files last.
> > 
> > What I came up with does not quite behave as I expected:
> > 
> > $ ls -al --color=never | sort -k1.1,1.1r -k8f 
> 
> You shouldn't ever need --color=never there unless you have aliased ls
> with ls --color=always.  You don't want ls --color=always (really you
> don't) and therefore you won't need to undo it with --color=never.

You're absolutely right. 

In fact I didn't want to have to worry about the effects of color escape
codes on sort field counting at that point and that's why I initially
specified --color=never.

On my system "ls" is aliased to "ls --color=auto".

Regrettably the man page provided on my system lists the three options
(never, always, auto) but does not give any explanation as to what they
actually do.

I did a 

$ ls -al | sort -k1.1,1.1r -k8f

and the output is identical (properly sorted with dots ignored)

OTOH, I have the "l" shortcut aliased to "ls -alh --full-time
--color=always" and I verified that

$ l | sort -k1.1,1.1r -k8f

screws up big time .. the output is "sort of" sorted .. 

Does --color=auto mean add colors when writing to a terminal and don't
add them when writing to a file (pipe etc.)..?

> > Why does .efile appear together with my other two [Ee]file's rather than
> > just below .clewn_keys?
> > 
> > Looks like sort is ignoring the dots .. ??
> 
> You probably have set a locale setting that ignores punctuation.

OK. This is beginning to make "sense". 

> > Side-effect of the "f" flag specified with my second sort key ..?
> 
> No.
> 
> > Something to do with my locale (en_US)?
> 
> Yes.  If a locale is set then the collation sequence for the locale is
> used.  This is controlled outside of sort (and also ls and bash and
> anything else that produces sorted output) and must be respected if
> set.
> 
>   http://www.gnu.org/software/coreutils/faq/#Sort-does-not-sort-in-normal-order_0021

Thanks.  Good doc.

> Apparently the people who defined the collating sequence for the en_*
> locales confused working with data on a computer with working with
> text on a computer.  The locale collating sequences for en_* ignores
> punctuation and folds case by default!

Given the symptoms and the nature of sort I would probably never have
figured that out myself. That there may be circumstances where this
comes in handy I do not doubt .. But as to making it the default for one
of (if not the) most widely-used locales?

> I have set the following in my environment to restore a standard sort
> ordering:
> 
>   export LANG=en_US.UTF-8 export LC_COLLATE=C

I gave  up on UTF-8 because I use mostly ELinks for browsing and afaik
it's not UTF-8 ready.

I tested with LC_ALL=POSIX (as recommended in your document) and the
"." was still being ignored.

So I issued the above export commands and (magically) data was sorted
as data .. 

Thank you very much for your clarification.