[9fans] test command

[9fans] test command

[Kenji Arisawa]

Hello,

"test" command of plan 9 has a operator "older", the usage is:
	test f -older t
where f is a file and t is a time.
however the command does not have "newer" operator.
why?

Kenji Arisawa

Re: [9fans] test command

[ron minnich]

On Wed, Sep 10, 2008 at 3:19 AM, Kenji Arisawa <arisawa@ar.aichi-u.ac.jp> wrote:
> Hello,
>
> "test" command of plan 9 has a operator "older", the usage is:
>        test f -older t
> where f is a file and t is a time.
> however the command does not have "newer" operator.
> why?
>

If a < b, and you want to know if b > a, can't you just do a < b?

ron

Re: [9fans] test command

[Rodolfo kix García]

a < b = !(a > b) + (a = b)

> On Wed, Sep 10, 2008 at 3:19 AM, Kenji Arisawa <arisawa@ar.aichi-u.ac.jp>
> wrote:
>> Hello,
>>
>> "test" command of plan 9 has a operator "older", the usage is:
>>        test f -older t
>> where f is a file and t is a time.
>> however the command does not have "newer" operator.
>> why?
>>
>
> If a < b, and you want to know if b > a, can't you just do a < b?
>
> ron
>
>


-- 
Rodolfo García AKA kix
http://www.kix.es/
EA4ERH (@IN80ER)

Re: [9fans] test command

[David Leimbach]

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On Wed, Sep 10, 2008 at 6:38 AM, ron minnich <rminnich@gmail.com> wrote:

> On Wed, Sep 10, 2008 at 3:19 AM, Kenji Arisawa <arisawa@ar.aichi-u.ac.jp>
> wrote:
> > Hello,
> >
> > "test" command of plan 9 has a operator "older", the usage is:
> >        test f -older t
> > where f is a file and t is a time.
> > however the command does not have "newer" operator.
> > why?
> >
>
> If a < b, and you want to know if b > a, can't you just do a < b?
>
> ron
>
>
Yeah with < and ! you can build anything you want :-)

Hence why many C++ STL comparisons just require you to make a functor for
less.

Dave

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Re: [9fans] test command

[Juan Céspedes]

Maybe I'm confused, but what Kenji said is that:

> "test" command of plan 9 has a operator "older", the usage is:
>        test f -older t
> where f is a file and t is a time.

If f is a file ant t is a *time*, you can't do test t -older f

Juan

Re: [9fans] test command

[Gorka Guardiola]

On Wed, Sep 10, 2008 at 5:27 PM, Juan Céspedes <cespedes@lsub.org> wrote:
> Maybe I'm confused, but what Kenji said is that:
>
>> "test" command of plan 9 has a operator "older", the usage is:
>>        test f -older t
>> where f is a file and t is a time.
>
> If f is a file ant t is a *time*, you can't do test t -older f
>

yes, but !older is the same as younger or equal.
!(test f -older t)
would be the same (equality notwithstanding)
as
test f -younger t

But then there is = and != for strings (for example), so this argument
is thin :-).
-- 
- curiosity sKilled the cat

Re: [9fans] test command

[Kenji Arisawa]

Hello,

On 2008/09/11, at 1:15, Gorka Guardiola wrote:
> yes, but !older is the same as younger or equal.

yes.

> But then there is = and != for strings (for example), so this argument
> is thin :-).

if we can easily get modified time of a file in the format of UNIX time,
where "easily" means "in the set of plan 9 commands".

Kenji Arisawa

Re: [9fans] test command

[erik quanstrom]

> > But then there is = and != for strings (for example), so this argument
> > is thin :-).
>
> if we can easily get modified time of a file in the format of UNIX time,
> where "easily" means "in the set of plan 9 commands".

there are certainly better ways to do this, but this works:

- erik

#!/bin/rc
rfork e

p='
$1 == "mtime:" {
	gsub("[()]", "", $8)
	print $8
}'

for(i){
	syscall -s fstat 0 buf 1024<$i>[2=1] |
		awk $p
}

Re: [9fans] test command

[Russ Cox]

> there are certainly better ways to do this, but this works:

as does /bin/mtime.

Re: [9fans] test command

[Kenji Arisawa]

Hello,

On 2008/09/11, at 11:38, Russ Cox wrote:

>> there are certainly better ways to do this, but this works:
>
> as does /bin/mtime.

I didn't know this command.

thanks russ and erik.

Kenji Arisawa