How come...

How come...

Post by kalasend at YAHOO dot CO » Wed, 09 May 2001 10:26:22



How come until today, Linux (or in general Unix) still does not have the
"undelete" feature?
 
 
 

How come...

Post by Jimbo » Wed, 09 May 2001 09:45:54



Quote:> How come until today, Linux (or in general Unix) still does not have the
> "undelete" feature?

It does! if you have sufficient disk space you can take 'snapshots' of your disk at
specified intervals so if you delete something by accident you can go to the snapshot
and copy that thing back to where it belongs.

 
 
 

How come...

Post by Jan Schauma » Wed, 09 May 2001 11:21:42



Quote:> How come until today, Linux (or in general Unix) still does not have the
> "undelete" feature?

Ho come even after decades people still delete files that they wish to
keep?

-Jan

--
Jan Schaumann <http://www.netmeister.org>

* JHM wonders what Joey did to earn "I'd just like to say, for the record,
  that Joey rules."        -- Seen on #Debian

 
 
 

How come...

Post by Dances With Cro » Wed, 09 May 2001 12:22:23


On Mon, 7 May 2001 18:26:22 -0700, kalasend at YAHOO dot COM staggered
into the Black Sun and said:

Quote:>How come until today, Linux (or in general Unix) still does not have
>the "undelete" feature?

Historical reasons.  Unix was a multi-user system from the very
beginning, and storage space was very expensive back in the early 70s.
So initially, when you rm'ed a file, its disk blocks were marked as
available immediately, and the file or parts of it got overwritten
whenever another user needed space.  The DOS way of doing things
(replace the first character of the filename with ASCII 206, marking the
file as "deleted") wouldn't have worked--storage space was too tight.
Ditto for the MacOS way of moving files to a "Trash" directory.

(Desktop environments like KDE and GNOME have implemented the MacOS
concept of a ~/Trash directory, so you *can* undelete things, sort of.
There is also the -i option to rm.)

The idea here is that the system does exactly what you tell it to do.
There's no bollocks about "The contents of this folder are not shown
because they are essential to the operation of the computer", you can
*y well rm -rf / if you want to.  Unix, in general, assumes that its
users know what they are doing.  Read Neal Stephenson's "In The
Beginning Was The Command Line", and pay close attention to the bit
about the Hole Hawg... he explains this far better than I could.

--
Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
Brainbench MVP for Linux Admin /  Workin' in a code mine, hittin' Ctrl-Alt
http://www.veryComputer.com/     /   Workin' in a code mine, whoops!
-----------------------------/    I hit a seg fault....

 
 
 

How come...

Post by Paul Kimo » Wed, 09 May 2001 12:32:56




Quote:> How come until today, Linux (or in general Unix) still does not have the
> "undelete" feature?

Because there needs to be a way to _really_ remove a file.  Your mission
is to convince everyone that they don't really want to use it.

--
Paul Kimoto
This message was originally posted on Usenet in plain text.  Any images,
hyperlinks, or the like shown here have been added without my consent,
and may be a violation of international copyright law.

 
 
 

How come...

Post by Eric » Wed, 09 May 2001 16:00:47


Quote:> How come until today, Linux (or in general Unix) still does not have the
> "undelete" feature?

Sure there is :

/home/a_user>touch a_file
/home/a_user>ls a_file
a_file
/home/a_user>rm a_file
deleting a_file
/home/a_user>ls a_file
ls: a_file: No such file or directory
/home/a_user>undelete a_file
undeleting "a_file"
/home/a_user>ls a_file
a_file
/home/a_user>

This is just a home made (un)delete.
You can easily maek one too. It's just a simple shell-script.
There are several scripts/programs that do the same, that you can
download from eg. freshmeat. (I made my own when I was just
learning to make shell-scripts) If you want my scripts, I can send them to
you.

Eric

 
 
 

How come...

Post by Harold Stevens US.972.952.32 » Wed, 09 May 2001 20:07:32



Quote:>How come until today, Linux (or in general Unix) still does not have the
>"undelete" feature?

This is a troll, right? If you're serious, consider this as well:

How come until today, Linux (or in general Unix) still does not have the
"defrag" feature?

Supposedly, *nix defrags exist, but I've not seen/required/used them. As
others suggested it's trivial to roll your own undelete scripts. So, how
do banks and other trivial pursuits do without "features" like this?

Undelete is for those who cannot manage their own backups. Defrag is for
file systems that cannot manage their own garbage. If you need them, you
should get an OS with them. Because *nix in general screams, and doesn't
have time for coddling. Business types seem to prefer this *nix style.

In short: A "feature" to some is a "PITA" to others.

--

Regards, Weird (Harold Stevens) * IMPORTANT EMAIL INFO FOLLOWS *
Pardon the bogus email domain (dseg etc.) in place for spambots.
Really it's (wyrd) at raytheon, dotted with com. DO NOT SPAM IT.
Standard Disclaimer: These are my opinions not Raytheon Company.

 
 
 

How come...

Post by Jean-David Beye » Wed, 09 May 2001 21:34:56



Quote:

> How come until today, Linux (or in general Unix) still does not have the
> "undelete" feature?

It does not need one. Do not delete files you wish to keep. If you
find yourself typing rm file_to_keep too often, you can alias rm to rm
-i and it will ask you if you really mean it before each delete. On my
machine, for example, the .bashrc for root contains (among other
things):

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

I do not do this for my users' accounts because I find it a nuisance.

In the rare cases where you delete a needed file, or where you
overwrite, one by mistake, you can always restore it from your backup.
My backups are done every morning at 1:03AM (or so), so I can always
restore to something less than 24 hours old.

--
 .~.  Jean-David Beyer           Registered Linux User 85642.
 /V\                             Registered Machine    73926.
/( )\ Shrewsbury, New Jersey     http://counter.li.org
^^-^^ 8:30am up 6 days, 23:41, 3 users, load average: 2.09, 2.15, 2.10

 
 
 

How come...

Post by Johan Kullsta » Wed, 09 May 2001 23:55:04



Quote:> On Mon, 7 May 2001 18:26:22 -0700, kalasend at YAHOO dot COM staggered
> into the Black Sun and said:
> >How come until today, Linux (or in general Unix) still does not have
> >the "undelete" feature?

> Historical reasons.  Unix was a multi-user system from the very
> beginning, and storage space was very expensive back in the early
> 70s.

TOPS-20 was a multiuser system from the 70s.  it had undelete and kept
a configurable number of back-up versions for you.  deleting a file
was a two step process.  first you cast "del" on them (which merely
marked them as dead, prevented "dir" from showing them by default, but
didn't free any space).  then you invoked "expunge" which would reap
all the files marked as dead.  in case you forgot, upon logout,
expunge would be automatically called.

i think ITS and VMS have (had?) similar systems but i do not have
first hand experience with them.

i liked the TOPS-20 system.  unix zealots will of course scoff.

you could probably finagle a system like it for unix.  create a shadow
tree of directories with hard links (either a kernel module or hack
libc to wrapper creat & friends).  normally files would have two
links.  rm removes one of them.  reap single linkers in the shadow
tree later.

--
J o h a n  K u l l s t a m

sysengr

 
 
 

How come...

Post by John Thompso » Thu, 10 May 2001 06:30:17



Quote:> How come until today, Linux (or in general Unix) still does not have the
> "undelete" feature?

That's what backups are for.  In a multi-user system any
filesystem-level undelete function becomes even less reliable.

--


 
 
 

How come...

Post by Grant Edwar » Thu, 10 May 2001 11:42:22



Quote:>>>into the Black Sun and said: How come until today, Linux (or in
>>>general Unix) still does not have the "undelete" feature?

>> Historical reasons.  Unix was a multi-user system from the
>> very beginning, and storage space was very expensive back in
>> the early 70s.

>TOPS-20 was a multiuser system from the 70s.  it had undelete and kept
>a configurable number of back-up versions for you.

 1) I suspect that the original Unix systems were far more resource
    starved than were TOPS-20 systems.  

 2) There were always other "cooler" features to add.  ;)

Quote:>i liked the TOPS-20 system.  unix zealots will of course scoff.

Nah.  I never used TOPS systems, but from everything I've read
they were quite elegant.

--
Grant Edwards                   grante             Yow!  I joined scientology
                                  at               at a garage sale!!
                               visi.com            

 
 
 

How come...

Post by Jerry Krep » Thu, 10 May 2001 21:35:40




> > How come until today, Linux (or in general Unix) still does not have the
> > "undelete" feature?

> That's what backups are for.  In a multi-user system any
> filesystem-level undelete function becomes even less reliable.

But, some distros, like SuSE, have a 'trash can'.  If you activate it and
then delete a file it is really just moved to the trash can until you
empty the trash or restore.  You can do the same thing yourself without
a 'trash can'.  Just move a file to /tmp, or make your own directory
called /trash.  When you are satisfied that you really meant to delete
a file you can empty your /tmp or /trash dir.
 
 
 

How come...

Post by Garglemonste » Thu, 10 May 2001 22:35:26



    >> On Mon, 7 May 2001 18:26:22 -0700, kalasend at YAHOO dot COM
    >> staggered into the Black Sun and said: >How come until today,
    >> Linux (or in general Unix) still does not have >the "undelete"
    >> feature?
    >>
    >> Historical reasons.  Unix was a multi-user system from the very
    >> beginning, and storage space was very expensive back in the
    >> early 70s.

    [...]

    Johan> i think ITS and VMS have (had?) similar systems but i do
    Johan> not have first hand experience with them.

vms did/does, but like most things vms, it was icky icky icky.  i
remember being hounded by admins to expunge shadow copies of files
whose names vms had obfuscated for its own nefarious and obscure
reasons.  *?  anyway, that site switched to unix and people were
happier.

g.m.

--

I'm having a tax-deductible experience!  I need an energy crunch!!

 
 
 

How come...

Post by Scott Stembaug » Fri, 11 May 2001 05:56:10





> > > How come until today, Linux (or in general Unix) still does not have
the
> > > "undelete" feature?

> > That's what backups are for.  In a multi-user system any
> > filesystem-level undelete function becomes even less reliable.

> But, some distros, like SuSE, have a 'trash can'.  If you activate it and
> then delete a file it is really just moved to the trash can until you
> empty the trash or restore.  You can do the same thing yourself without
> a 'trash can'.  Just move a file to /tmp, or make your own directory
> called /trash.  When you are satisfied that you really meant to delete
> a file you can empty your /tmp or /trash dir.

This was how I handled it in the early 80s when there were still several
versions of DOS to choose from and PCs were way out of my budget.  I aliased
rm to mv the file to a /tmp/username/garbage dir and in the .logout I would
ls the dir and ask the user about cleanup issues.  Seemed simple enough.  I
still use that today on all of my personal boxes.

--scott

 
 
 

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