Desired behaviour of "ifconfig -alias"

JoaoBR joao at
Mon Feb 12 19:54:43 UTC 2007

On Monday 12 February 2007 16:09, Oliver Fromme wrote:
>  >
>  > it is not misleading and it is a perfect term. With alias you add
>  > secondary addresses to an interface. Like secondary is probably the
>  > better word,
> No, not at all.  As soon as you use the terms "primary IP
> address" and "secondary IP addresses", you imply that they
> are not equal.  But they are equal.  It's just a list of
> IP addresses assigned to an interface which happens to have
> a certain order.

nobody claims that there is an master-slave order or something, alias is the 
secondary in order of time, but not in value, I do not even understand why 
you talking so much about this, the point is more than clear 

> Yes, that's why I wrote it should be changed to not contain
> the word "alias" anymore, but simply an enumerated list.
>  > > If no IP address is specified, then it's not completely
>  > > nonsensical to remove the first address.  In fact I've
>  > > used that short-cut to quickly remove the only address
>  > > from an interface.  I've used "ifconfig xyz0 delete"
>  > > quite a lot.
>  >

yes it is! it does not matter which word, without an IP address it should NOT 
remove anything

>  > the man page tells us that -alias removes *the* specified address and
>  > not the first, also the man page does not say that there is any further
>  > action when *no* IP address specified
> That's true.  Usually if something is not documented, the
> behaviour is undefined.

undefined is absolutely not similar to remove something ..

>  > delete is according to the man page another word for -alias, that means,
>  > using grammatical logic that -alias is the main command,
> No.  It means that "delete" and "remove" are aliases for
> "-alias".  In reality they're simply equal.  ;-)
>  > then according to the man
>  > page there is no other command as "-alias *IP*" to remove an IP address
>  > and -alias only should not remove anything
> It's not documented that way.  As I wrote above.
> If something is not documented, that doesn't mean that it
> shouldn't do anything at all.  In that case a _lot_ of
> things wouldn't work.  :-)

all commands which remove something "usally" say something when trying to use 
without value, rm, rmdir, rmuser ... I really do not remember any other 
then -alias which does so

>  > you see, now you apply logic because you want to and when not not ... ;)
>  >
>  > to let it more clear what I mean, you say: "you don't tell it anything
>  > to add" so why the heck "ifconfig nic -alias" should remove one if I do
>  > not tell so?
> In the case of adding something, what should be added if
> nothing is specified?  Should the tool invent an arbitrary
> IP address and add it?  Now that would be nonsensical.
> But when removing something without specifying which one,
> it makes some sense to simply remove the first existing
> address on that interface.  It would even be OK with me
> to remove the last one, or an arbitrary one -- I use that
> shortcut mostely when I need to remove the only address
> from an interface (or all existing addresses), so it
> doesn't matter.

come on, now your are looking up a way out of this mess ...

> In fact, it might also make sense to enhance the syntax
> to allow the specification of a number, for example
> "ifconfig xyz0 delete #2" would remove the second address

my god what a horrible idea is that! do you remember "#" in UNIX????

the command "ifconfig nic -alias IP" is OK, perfect, even delete is, the 
problem and the only problem is that both remove without specifying a value a 
value and that *IS* wrong behaviour, otherwise *you* must agree that rm 
removes the first file it finds, rmuser the first user and and and, that is 
wrong, documented or not

> However, such a feature will run into problems when the
> set of ip addresses is not an ordered list anymore, which
> might very well happen in the future.  Then there will be
> no "first" and "last" anymore, but instead the interface
> will just have an unordered set of IP addresses.  In fact
> I wish that would already be the case, so people saying
> "primary" and "secondary" would shut up already.  :-)

then they come up in  random order on each "ifconfig nic" :) ???



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