[U-Boot-Users] Delete all env vars except read onlys

[U-Boot-Users] Delete all env vars except read onlys

[Matthias Fuchs]

Hi,

I am wondering if there is a way to delete all environment variables
but not the readonly ones. The common way to delete all variables
is to make the environment CRC invalid an do a reset. After reset
a saveenv saves a default environment. 

What I want to do is to delete all variables (preferable from an autoscr script)
but not the vendor variables like serial# and eth?addr.

Wildcards in the setenv parameters would solve this issue, 
but chars like '*' or '?' are valid chars for environment variables.

Any idea?

Matthias

[U-Boot-Users] Delete all env vars except read onlys

[Stefan Roese]

Hi Matthias,

On Tuesday 12 February 2008, Matthias Fuchs wrote:
> I am wondering if there is a way to delete all environment variables
> but not the readonly ones. The common way to delete all variables
> is to make the environment CRC invalid an do a reset. After reset
> a saveenv saves a default environment.
>
> What I want to do is to delete all variables (preferable from an autoscr
> script) but not the vendor variables like serial# and eth?addr.
>
> Wildcards in the setenv parameters would solve this issue,
> but chars like '*' or '?' are valid chars for environment variables.
>
> Any idea?

I don't know of such a solution. But such a "feature" would be handy 
sometimes. So perhaps this needs to get implemented as a new U-Boot command. 
But you should be careful. Such a command should require probably a password, 
to that users don't unintentionally erase their environment.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <200802120944.42632.matthias.fuchs@esd-electronics.com> you wrote:
> 
> I am wondering if there is a way to delete all environment variables
> but not the readonly ones. The common way to delete all variables
> is to make the environment CRC invalid an do a reset. After reset
> a saveenv saves a default environment. 
> 
> What I want to do is to delete all variables (preferable from an autoscr script)
> but not the vendor variables like serial# and eth?addr.
> 
> Wildcards in the setenv parameters would solve this issue, 
> but chars like '*' or '?' are valid chars for environment variables.
> 
> Any idea?

There is no direct way; you may write a small standalone application...

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Extended Epstein-Heisenberg Principle: In an R & D orbit, only  2  of
the  existing 3 parameters can be defined simultaneously. The parame-
ters are: task, time and resources ($).

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <200802121549.49402.sr@denx.de> you wrote:
> 
> I don't know of such a solution. But such a "feature" would be handy 
> sometimes. So perhaps this needs to get implemented as a new U-Boot command. 
> But you should be careful. Such a command should require probably a password, 
> to that users don't unintentionally erase their environment.

Please don't do passwords in U-Boot (btw - it might be difficult,  as
the logical way to store these would be in the environment :-)

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Conscious is when you are aware of something, and conscience is  when
you wish you weren't.

[U-Boot-Users] Delete all env vars except read onlys

[Matthias Fuchs]

Hi Stefan,

what about a 'scrubenv' or 'cleanenv' command that tries to unset all 
variables leaving readonlys untouched.

The command could request a confirmation:

=> scrubenv
Do you really want to do this ('yes' or 'no')? yes
Can't overwrite "serial#"
Can't overwrite "ethaddr"
=> saveenv

The above output is faked. So I did not start coding :-)

What do you think?

Matthias

On Tuesday 12 February 2008 15:49, Stefan Roese wrote:
> Hi Matthias,
> 
> On Tuesday 12 February 2008, Matthias Fuchs wrote:
> > I am wondering if there is a way to delete all environment variables
> > but not the readonly ones. The common way to delete all variables
> > is to make the environment CRC invalid an do a reset. After reset
> > a saveenv saves a default environment.
> >
> > What I want to do is to delete all variables (preferable from an autoscr
> > script) but not the vendor variables like serial# and eth?addr.
> >
> > Wildcards in the setenv parameters would solve this issue,
> > but chars like '*' or '?' are valid chars for environment variables.
> >
> > Any idea?
> 
> I don't know of such a solution. But such a "feature" would be handy 
> sometimes. So perhaps this needs to get implemented as a new U-Boot command. 
> But you should be careful. Such a command should require probably a password, 
> to that users don't unintentionally erase their environment.
> 
> Best regards,
> Stefan

[U-Boot-Users] Delete all env vars except read onlys

[Stefan Roese]

Hi Matthias,

On Wednesday 13 February 2008, Matthias Fuchs wrote:
> what about a 'scrubenv' or 'cleanenv' command that tries to unset all
> variables leaving readonlys untouched.

Or 'resetenv'?

> The command could request a confirmation:
>
> => scrubenv
> Do you really want to do this ('yes' or 'no')? yes
> Can't overwrite "serial#"
> Can't overwrite "ethaddr"
> => saveenv

Yes, I was just thinking (while showering, no joke) about this and had the 
same idea with an 'yes' check. :)

> The above output is faked. So I did not start coding :-)
>
> What do you think?

Looks good to me.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] Delete all env vars except read onlys

[Matthias Fuchs]

Hi Stefan,

On Wednesday 13 February 2008 09:56, Stefan Roese wrote:
> Hi Matthias,
> 
> On Wednesday 13 February 2008, Matthias Fuchs wrote:
> > what about a 'scrubenv' or 'cleanenv' command that tries to unset all
> > variables leaving readonlys untouched.
> 
> Or 'resetenv'?
All the same to me with the name. As always it will be the most complicated
part. I have to remember the 'ethrotate' variable :-)

> 
> > The command could request a confirmation:
> >
> > => scrubenv
> > Do you really want to do this ('yes' or 'no')? yes
> > Can't overwrite "serial#"
> > Can't overwrite "ethaddr"
> > => saveenv
> 
> Yes, I was just thinking (while showering, no joke) about this and had the 
> same idea with an 'yes' check. :)
Do not get into details :-)
> 
> > The above output is faked. So I did not start coding :-)
> >
> > What do you think?
> 
> Looks good to me.
I put it on my list.

Matthias

[U-Boot-Users] Delete all env vars except read onlys

[Markus Klotzbücher]

Matthias Fuchs <matthias.fuchs@esd-electronics.com> writes:

> what about a 'scrubenv' or 'cleanenv' command that tries to unset all 
> variables leaving readonlys untouched.
>
> The command could request a confirmation:
>
> => scrubenv
> Do you really want to do this ('yes' or 'no')? yes

Such a confirmation is not very Unix-like and will prevent this command
to be used in scripts. I like the idea of a scrubenv/resetenv command
but vote for leaving out the confirmation.

U-Boot provides many, much more serious ways to blow you foot off which
don't ask such questions.

Best regards

Markus Klotzbuecher

--
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de

[U-Boot-Users] Delete all env vars except read onlys

[Stefan Roese]

On Wednesday 13 February 2008, Markus Klotzb?cher wrote:
> > => scrubenv
> > Do you really want to do this ('yes' or 'no')? yes
>
> Such a confirmation is not very Unix-like and will prevent this command
> to be used in scripts. I like the idea of a scrubenv/resetenv command
> but vote for leaving out the confirmation.
>
> U-Boot provides many, much more serious ways to blow you foot off which
> don't ask such questions.

Sure. But not by "just" typing one command. Or at least I don't know those 
kind of destructive commands.

So I still would like to see the extra check.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] Delete all env vars except read onlys

[Markus Klotzbücher]

Stefan Roese <sr@denx.de> writes:

> On Wednesday 13 February 2008, Markus Klotzb?cher wrote:
>> > => scrubenv
>> > Do you really want to do this ('yes' or 'no')? yes
>>
>> Such a confirmation is not very Unix-like and will prevent this command
>> to be used in scripts. I like the idea of a scrubenv/resetenv command
>> but vote for leaving out the confirmation.
>>
>> U-Boot provides many, much more serious ways to blow you foot off which
>> don't ask such questions.
>
> Sure. But not by "just" typing one command. Or at least I don't know those 
> kind of destructive commands.

It need not be a single one, it could be a script. For instance, I once
ran an "update" script without checking that _my_ version of U-Boot
would be used. It used some ancient version which turned the board
(temporarily) into a doorstop.

Stupid? Yes! But would such checks (e.g. to "mw") have avoided the
problem?  I doubt it. Probably I'd just have typed "yes" without
checking.

BTW, after accidentally erasing the environment variables U-Boot will
(likely) still start up, so it's really not that critical, is it?

Just my 2c.

Best regards

     Markus

--
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de

[U-Boot-Users] Delete all env vars except read onlys

[Detlev Zundel]

Hi,

> Stefan Roese <sr@denx.de> writes:
>
>> On Wednesday 13 February 2008, Markus Klotzb?cher wrote:
>>> > => scrubenv
>>> > Do you really want to do this ('yes' or 'no')? yes
>>>
>>> Such a confirmation is not very Unix-like and will prevent this command
>>> to be used in scripts. I like the idea of a scrubenv/resetenv command
>>> but vote for leaving out the confirmation.
>>>
>>> U-Boot provides many, much more serious ways to blow you foot off which
>>> don't ask such questions.
>>
>> Sure. But not by "just" typing one command. Or at least I don't know those 
>> kind of destructive commands.
>
> It need not be a single one, it could be a script. For instance, I once
> ran an "update" script without checking that _my_ version of U-Boot
> would be used. It used some ancient version which turned the board
> (temporarily) into a doorstop.
>
> Stupid? Yes! But would such checks (e.g. to "mw") have avoided the
> problem?  I doubt it. Probably I'd just have typed "yes" without
> checking.
>
> BTW, after accidentally erasing the environment variables U-Boot will
> (likely) still start up, so it's really not that critical, is it?

Why not do both?  Unix untilities do it sometimes this way: Use an
interactive check for "scrubenv" but allow "scrubenv -force" not to
ask.  As many of the U-Boot users know Unix, this would follow from the
"principle of least surprise"...

Cheers
  Detlev

-- 
Progress in  mathematics comes from  repeated acts of generalization.
If mathematics is anything, it is the art of chosing the most elegant
generalization for some abstract pattern.  Thus esthetics is central.
                                     -- Douglas Hofstadter
--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de

[U-Boot-Users] Delete all env vars except read onlys

[Markus Klotzbücher]

Detlev Zundel <dzu@denx.de> writes:

>> Stefan Roese <sr@denx.de> writes:
>>
>>> On Wednesday 13 February 2008, Markus Klotzb?cher wrote:
>>>> > => scrubenv
>>>> > Do you really want to do this ('yes' or 'no')? yes
>>>>
>>>> Such a confirmation is not very Unix-like and will prevent this command
>>>> to be used in scripts. I like the idea of a scrubenv/resetenv command
>>>> but vote for leaving out the confirmation.
>>>>
>>>> U-Boot provides many, much more serious ways to blow you foot off which
>>>> don't ask such questions.
>>>
>>> Sure. But not by "just" typing one command. Or at least I don't know those 
>>> kind of destructive commands.
>>
>> It need not be a single one, it could be a script. For instance, I once
>> ran an "update" script without checking that _my_ version of U-Boot
>> would be used. It used some ancient version which turned the board
>> (temporarily) into a doorstop.
>>
>> Stupid? Yes! But would such checks (e.g. to "mw") have avoided the
>> problem?  I doubt it. Probably I'd just have typed "yes" without
>> checking.
>>
>> BTW, after accidentally erasing the environment variables U-Boot will
>> (likely) still start up, so it's really not that critical, is it?
>
> Why not do both?  Unix untilities do it sometimes this way: Use an
> interactive check for "scrubenv" but allow "scrubenv -force" not to
> ask.  As many of the U-Boot users know Unix, this would follow from the
> "principle of least surprise"...

Yeah, why not both. That's fine with me!

Best regards

Markus Klotzb?cher

--
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de

[U-Boot-Users] Delete all env vars except read onlys

[Stefan Roese]

On Wednesday 13 February 2008, Markus Klotzb?cher wrote:
> > Why not do both?  Unix untilities do it sometimes this way: Use an
> > interactive check for "scrubenv" but allow "scrubenv -force" not to
> > ask.  As many of the U-Boot users know Unix, this would follow from the
> > "principle of least surprise"...
>
> Yeah, why not both. That's fine with me!

Yes, I like it too.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <200802130921.38894.matthias.fuchs@esd-electronics.com> you wrote:
> 
> what about a 'scrubenv' or 'cleanenv' command that tries to unset all 
> variables leaving readonlys untouched.

Make this "clearenv", please.

> The command could request a confirmation:

No.

> => scrubenv
> Do you really want to do this ('yes' or 'no')? yes

No. Such code will not go into U-Boot.

"UNIX was not designed to stop you from doing stupid things,  because
that would also stop you from doing clever things."       - Doug Gwyn

> Can't overwrite "serial#"
> Can't overwrite "ethaddr"

I would not print such messages, especially since you aren't
overwriting these. If you want, print a similar warning as used by the
"erase" command for protected flash sectors, i. e. something like:

	=> cleanenv
	Warning: 5 protected variables will not be cleared
	=>

> What do you think?

Looks good to me...

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Voodoo Programming: Things programmers do that  they  know  shouldn't
work  but they try anyway, and which sometimes actually work, such as
recompiling everything.                             - Karl Lehenbauer

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <200802131113.08367.sr@denx.de> you wrote:
>
> > U-Boot provides many, much more serious ways to blow you foot off which
> > don't ask such questions.
> 
> Sure. But not by "just" typing one command. Or at least I don't know those
> kind of destructive commands.

=> prot off all; era all

> So I still would like to see the extra check.

Nope. I will NAK it. Markus is absolutley right.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Let the programmers be many and the managers few -- then all will  be
productive.               -- Geoffrey James, "The Tao of Programming"

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <m23arxun23.fsf@ohwell.denx.de> you wrote:
> 
> Why not do both? Unix untilities do it sometimes this way: Use an
> interactive check for "scrubenv" but allow "scrubenv -force" not to
> ask. As many of the U-Boot users know Unix, this would follow from
> the "principle of least surprise"...

That would be exactly the other way round, i. e. provide an optional
"-i" argument like "rm *" is doing in Unix.

The default shall be not to ask any questions.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
They say, well, meybe it _is_ smelly, maybe it _is_ overcrowded, may-
be it _is_ a bit like Hell would be if they shut the  fires  off  and
stabled  a  herd  of  incontinent cows there for a year, but you must
admit that it is full of sheer, vibrant, dynamic _life_.
                                 - Terry Pratchett, _Moving Pictures_

[U-Boot-Users] Delete all env vars except read onlys

[Scott Wood]

Wolfgang Denk wrote:
> In message <m23arxun23.fsf@ohwell.denx.de> you wrote:
>> Why not do both? Unix untilities do it sometimes this way: Use an
>> interactive check for "scrubenv" but allow "scrubenv -force" not to
>> ask. As many of the U-Boot users know Unix, this would follow from
>> the "principle of least surprise"...
> 
> That would be exactly the other way round, i. e. provide an optional
> "-i" argument like "rm *" is doing in Unix.
> 
> The default shall be not to ask any questions.

rm defaults to not asking questions in *some* cases, but to asking in 
others.  Hence the -f flag to rm.

-Scott

[U-Boot-Users] Delete all env vars except read onlys

[Scott Wood]

Wolfgang Denk wrote:
> In message <200802131113.08367.sr@denx.de> you wrote:
>>> U-Boot provides many, much more serious ways to blow you foot off which
>>> don't ask such questions.
>> Sure. But not by "just" typing one command. Or at least I don't know those
>> kind of destructive commands.
> 
> => prot off all; era all

There's a slight difference between two commands with arguments versus 
one command with none.

-Scott

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <47B37416.8090708@freescale.com> you wrote:
>
> > That would be exactly the other way round, i. e. provide an optional
> > "-i" argument like "rm *" is doing in Unix.
> > 
> > The default shall be not to ask any questions.
> 
> rm defaults to not asking questions in *some* cases, but to asking in 
> others.  Hence the -f flag to rm.

Oops??? "rm" never asks unless you ask it to ask.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Q:  How do you play religious roulette?
A:  You stand around in a circle  and  blaspheme  and  see  who  gets
    struck by lightning first.

[U-Boot-Users] Delete all env vars except read onlys

[Scott Wood]

Wolfgang Denk wrote:
> In message <47B37416.8090708@freescale.com> you wrote:
>>> That would be exactly the other way round, i. e. provide an optional
>>> "-i" argument like "rm *" is doing in Unix.
>>>
>>> The default shall be not to ask any questions.
>> rm defaults to not asking questions in *some* cases, but to asking in 
>> others.  Hence the -f flag to rm.
> 
> Oops??? "rm" never asks unless you ask it to ask.

Not true.  It will ask if you don't have write permission to the file, 
even if you are able to delete because you have write permission to the 
directory.

The -f flag wouldn't be there if it were a no-op...

-Scott

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <47B37430.8070008@freescale.com> you wrote:
>
> > => prot off all; era all
> 
> There's a slight difference between two commands with arguments versus 
> one command with none.

Well, as Markus  already  wote,  there  are  so  many  ways  to  kill
yourself.  If  you don't accept the line above, just try "run update"
without loading a (valid) image first.


Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
One essential to success is that you desire be an all-obsessing  one,
your thoughts and aims be co-ordinated, and your energy be concentra-
ted and applied without letup.

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <47B37791.3010109@freescale.com> you wrote:
>
> > Oops??? "rm" never asks unless you ask it to ask.
> 
> Not true.  It will ask if you don't have write permission to the file, 
> even if you are able to delete because you have write permission to the 
> directory.

Does it? Indeed. Must be a GNUism. I bet this was't there in Unix v6
when I learned it ;-)


You are right, but this  is  still  a  special  case  where  another,
explicit protection is being overwritten.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
You got to learn three things. What's  real,  what's  not  real,  and
what's the difference."           - Terry Pratchett, _Witches Abroad_

[U-Boot-Users] Delete all env vars except read onlys

[Stefan Roese]

On Wednesday 13 February 2008, Scott Wood wrote:
> Wolfgang Denk wrote:
> > In message <200802131113.08367.sr@denx.de> you wrote:
> >>> U-Boot provides many, much more serious ways to blow you foot off which
> >>> don't ask such questions.
> >>
> >> Sure. But not by "just" typing one command. Or at least I don't know
> >> those kind of destructive commands.
> >
> > => prot off all; era all
>
> There's a slight difference between two commands with arguments versus
> one command with none.

Yes, there is a big difference for my taste.

I would still prefer the version with the '--force' parameter. Just my 2 
cents.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <200802140620.15102.sr@denx.de> you wrote:
>
> I would still prefer the version with the '--force' parameter. Just my 2 
> cents.

I really don't want to have this, for two reasons: 1) U-Boot doesn't
do "Do you really want to" confirmations, because these don't fit into
the Unix design philisophy; 2) U-Boot doesn't do GNU style long
command line switches (for several reasons, memory footprint being one
of them).

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Quantum Mechanics is God's version of "Trust me."

[U-Boot-Users] Delete all env vars except read onlys

[Detlev Zundel]

Hi,

> In message <47B37791.3010109@freescale.com> you wrote:
>>
>> > Oops??? "rm" never asks unless you ask it to ask.
>> 
>> Not true.  It will ask if you don't have write permission to the file, 
>> even if you are able to delete because you have write permission to the 
>> directory.
>
> Does it? Indeed. Must be a GNUism. I bet this was't there in Unix v6
> when I learned it ;-)
>
>
> You are right, but this  is  still  a  special  case  where  another,
> explicit protection is being overwritten.

* mkfs.ext2 on a file, needs -F package managers with unfulfilled
* dependencies always ask and need a "--force-xxx" to go ahead
  whatsoever.
* bzip2, bunzip2, bzcat, gzip, gzcat, gunzip -f to overwrite files 
* git-checkout-index needs -f to overwrite files
* git-push needs -f to push non-linear head
* git-fetch needs -f in same situtation
* rsync -force to force deletion of dirs even if not empty
....

I'll stop here.  It seems the unix commandline tilted to a behaviour
where interactive commands tend to ask in dangerous situations but
scripts can explicitely override it - which is definitely what I
prefer.

Cheers
  Detlev

-- 
Woman who seek to be equal with men lack ambition
                       -- Timothy Leary
--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de

[U-Boot-Users] Delete all env vars except read onlys

[Detlev Zundel]

Hi Wolfgang,

> In message <200802140620.15102.sr@denx.de> you wrote:
>>
>> I would still prefer the version with the '--force' parameter. Just my 2 
>> cents.
>
> I really don't want to have this, for two reasons: 1) U-Boot doesn't
> do "Do you really want to" confirmations, because these don't fit into
> the Unix design philisophy; 2) U-Boot doesn't do GNU style long
> command line switches (for several reasons, memory footprint being one
> of them).

As I hinted at in my other mail, git is my prime example of living up to
the spirit of unix - and still many commands there, e.g. git-push need a
'-f' to prevent clobbering costly changes inadvertently.

In my opinion your argument 1) is not true as it stands.  Unix wants its
users to be as productive as possible and typing two extra characters
when ommitting them can cause hours of work is definitely in this
spirit.  

Exaggerating your argument I would ask why you do not work only as root
on your machine.  In U-Boot we do not have this "user" level of
protection so IMHO it makes sense to have at least a bit of it.

It is true however that we don't have any kind of option processing, so
probably '-force' wasn't a good choice to begin with.  What about only
using "all" as a "conformative" option?

Cheers
  Detlev

-- 
Perfection (in design) is achieved not when there is nothing more to add,
but rather when there is nothing more to take away.
                                        -- Antoine de Saint-Exupery
--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <m27ih6p68o.fsf@ohwell.denx.de> you wrote:
> 
> As I hinted at in my other mail, git is my prime example of living up to
> the spirit of unix - and still many commands there, e.g. git-push need a
> '-f' to prevent clobbering costly changes inadvertently.

The important point is the "inadvertently". It is OK if you need an
overwrite flag for commands that in the normal course of action are
non-destructive, but in special situations are.

However, commands which are designed to cause "destructive" actions
don't ask:

* rm does not ask by default. Not even for "rm -r *"
* mkfs does not ask normally - it will happily kill the whole
  partition's content
* cp or mv will happily overwrite target files (assuming sufficient
  permissions)
etc.

The  "clearenv"  command  has  a  well-defined  purpose:  clear   the
environment.  Similar  like  "erase" will clear the flash. Or "cp" or
"mw" will overwrite even vital parts of the RAM. No  questions  being
asked.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Bus error -- please leave by the rear door.

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

Uff....

After a longish  discussion  with  Detlev  we  came  up  with  a  new
proposal,  which  hopefully  is  acceptable  to all. We agreed that a
command name like "clearenv" or "scrubenv" or similar (which  doesn't
require  any  arguments) might be too dangerous for the unexperienced
user why randomly types commands "just  to  see  what  happens".  For
example,  even  if you type "erase" it will not do any damage because
arguments are missing - but "erase all" will blow away most  of  your
flash content without asking.

So the idea is to call the new command "environment" (or short "env");
usage would be then:

	=> env clear

to clear the envrionment (except read-only variables); thsi also
allows for pretty useful additional functionality like this:

	=> env default

to reset the environment to the (compiled in) default settings.

One might even consider something like

	=> env clear all

to blow away the whole env, including the read-only variables.


Would that be acceptable to everybody?



Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"There is such a fine line between genius and stupidity."
- David St. Hubbins, "Spinal Tap"

[U-Boot-Users] Delete all env vars except read onlys

[Markus Klotzbücher]

Wolfgang Denk <wd@denx.de> writes:

> After a longish  discussion  with  Detlev  we  came  up  with  a  new
> proposal,  which  hopefully  is  acceptable  to all. We agreed that a
> command name like "clearenv" or "scrubenv" or similar (which  doesn't
> require  any  arguments) might be too dangerous for the unexperienced
> user why randomly types commands "just  to  see  what  happens".  For
> example,  even  if you type "erase" it will not do any damage because
> arguments are missing - but "erase all" will blow away most  of  your
> flash content without asking.

[...]

> Would that be acceptable to everybody?

Sounds good!

Best regards

Markus Klotzb?cher

--
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de

[U-Boot-Users] Delete all env vars except read onlys

[Jean-Christophe PLAGNIOL-VILLARD]

On 17:40 Fri 15 Feb     , Wolfgang Denk wrote:
> Uff....
> 
> After a longish  discussion  with  Detlev  we  came  up  with  a  new
> proposal,  which  hopefully  is  acceptable  to all. We agreed that a
> command name like "clearenv" or "scrubenv" or similar (which  doesn't
> require  any  arguments) might be too dangerous for the unexperienced
> user why randomly types commands "just  to  see  what  happens".  For
> example,  even  if you type "erase" it will not do any damage because
> arguments are missing - but "erase all" will blow away most  of  your
> flash content without asking.
> 
> So the idea is to call the new command "environment" (or short "env");
> usage would be then:
> 
> 	=> env clear
> 
> to clear the envrionment (except read-only variables); thsi also
> allows for pretty useful additional functionality like this:
> 
> 	=> env default
> 
> to reset the environment to the (compiled in) default settings.
> 
> One might even consider something like
> 
> 	=> env clear all
> 
> to blow away the whole env, including the read-only variables.
> 
> 
> Would that be acceptable to everybody?
> 
> 
Ack-By : Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

Best Regards,
J.

[U-Boot-Users] Delete all env vars except read onlys

[Martin Krause]

u-boot-users-bounces at lists.sourceforge.net wrote on :
> Uff....
> 
> After a longish  discussion  with  Detlev  we  came  up  with  a  new
> proposal,  which  hopefully  is  acceptable  to all. We agreed that a
> command name like "clearenv" or "scrubenv" or similar (which  doesn't
> require  any  arguments) might be too dangerous for the unexperienced
> user why randomly types commands "just  to  see  what  happens".  For
> example,  even  if you type "erase" it will not do any damage because
> arguments are missing - but "erase all" will blow away most  of  your
> flash content without asking.
> 
> So the idea is to call the new command "environment" (or short "env");
> usage would be then:
> 
> 	=> env clear
> 
> to clear the envrionment (except read-only variables); thsi also
> allows for pretty useful additional functionality like this:
> 
> 	=> env default

This would be a very nice feature. With this command no knowledge is
needed in which sector(s) the environment is stored. This would be
very convenient in our production or service department, because
all our different boards could be reseted to a known state with the
same command.

> 
> to reset the environment to the (compiled in) default settings.
> 
> One might even consider something like
> 
> 	=> env clear all
> 
> to blow away the whole env, including the read-only variables.
> 
> 
> Would that be acceptable to everybody?

No objections!

Best Regards,
Martin Krause

--
TQ-Systems GmbH
Muehlstrasse 2, Gut Delling, D-82229 Seefeld
Amtsgericht Muenchen, HRB 105 018, UST-IdNr. DE 811 607 913
Geschaeftsfuehrer: Dipl.-Ing. (FH) Detlef Schneider, Dipl.-Ing. (FH) Ruediger Stahl
http://www.tq-group.com

[U-Boot-Users] Delete all env vars except read onlys

[Matthias Fuchs]

Hi, 

yes, I can live with the 'env' command, too. Sound's good to me.

Matthias

On Friday 15 February 2008 21:27:20 Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 17:40 Fri 15 Feb     , Wolfgang Denk wrote:
> > Uff....
> >
> > After a longish  discussion  with  Detlev  we  came  up  with  a  new
> > proposal,  which  hopefully  is  acceptable  to all. We agreed that a
> > command name like "clearenv" or "scrubenv" or similar (which  doesn't
> > require  any  arguments) might be too dangerous for the unexperienced
> > user why randomly types commands "just  to  see  what  happens".  For
> > example,  even  if you type "erase" it will not do any damage because
> > arguments are missing - but "erase all" will blow away most  of  your
> > flash content without asking.
> >
> > So the idea is to call the new command "environment" (or short "env");
> > usage would be then:
> >
> > 	=> env clear
> >
> > to clear the envrionment (except read-only variables); thsi also
> > allows for pretty useful additional functionality like this:
> >
> > 	=> env default
> >
> > to reset the environment to the (compiled in) default settings.
> >
> > One might even consider something like
> >
> > 	=> env clear all
> >
> > to blow away the whole env, including the read-only variables.
> >
> >
> > Would that be acceptable to everybody?
>
> Ack-By : Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
>
> Best Regards,
> J.
>
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[U-Boot-Users] Delete all env vars except read onlys

[Ulf Samuelsson]

>> >
>> > After a longish  discussion  with  Detlev  we  came  up  with  a  new
>> > proposal,  which  hopefully  is  acceptable  to all. We agreed that a
>> > command name like "clearenv" or "scrubenv" or similar (which  doesn't
>> > require  any  arguments) might be too dangerous for the unexperienced
>> > user why randomly types commands "just  to  see  what  happens".  For
>> > example,  even  if you type "erase" it will not do any damage because
>> > arguments are missing - but "erase all" will blow away most  of  your
>> > flash content without asking.
>> >
>> > So the idea is to call the new command "environment" (or short "env");
>> > usage would be then:
>> >
>> > => env clear
>> >
>> > to clear the envrionment (except read-only variables); thsi also
>> > allows for pretty useful additional functionality like this:
>> >
>> > => env default
>> >
>> > to reset the environment to the (compiled in) default settings.
>> >

I see this as essential and have implemented this in my own u-boot.
I call it "defenv".

It is a little different though, It will reinitialize the predefined environment
variables to default settings but will not touch the other.

If "env default" is implemented the same way, then you could get a 
100% clean environment by:

env clear ; env default

What will "env" do without parameters?




Best Regards
Ulf Samuelsson

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <00ca01c8740c$5a7b9fe0$c3031c0a@atmel.com> you wrote:
> 
> It is a little different though, It will reinitialize the predefined
> environment
> variables to default settings but will not touch the other.

Makes sense.

> If "env default" is implemented the same way, then you could get a 
> 100% clean environment by:
> 
> env clear ; env default

I see.

> What will "env" do without parameters?

As usual: it will print it's "usage"  message  and  return  an  error
code.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"If you are afraid of loneliness, don't marry."             - Chekhov

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <200802202217.58210.matthias.fuchs@esd-electronics.com> you wrote:
> 
> yes, I can live with the 'env' command, too. Sound's good to me.

Hm... and who will submit the patch?

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
A bore is someone who persists in holding his own views after we have
enlightened him with ours.

[U-Boot-Users] Delete all env vars except read onlys

[Wolfgang Denk]

In message <20080215164010.2944E24D11@gemini.denx.de> I wrote:
> 
> After a longish  discussion  with  Detlev  we  came  up  with  a  new
> proposal,  which  hopefully  is  acceptable  to all. We agreed that a
> command name like "clearenv" or "scrubenv" or similar (which  doesn't
> require  any  arguments) might be too dangerous for the unexperienced
> user why randomly types commands "just  to  see  what  happens".  For
> example,  even  if you type "erase" it will not do any damage because
> arguments are missing - but "erase all" will blow away most  of  your
> flash content without asking.
> 
> So the idea is to call the new command "environment" (or short "env");
> usage would be then:
> 
> 	=> env clear
> 
> to clear the envrionment (except read-only variables); thsi also
> allows for pretty useful additional functionality like this:
> 
> 	=> env default
> 
> to reset the environment to the (compiled in) default settings.
> 
> One might even consider something like
> 
> 	=> env clear all
> 
> to blow away the whole env, including the read-only variables.
> 
> 
> Would that be acceptable to everybody?

There was general agreement that this was a good thing, but I haven't
seen any actual code yet.

I anybody working on this?

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Q:  Do you know what the death rate around here is?
A:  One per person.