!!! WARNING TO CROOMBE, READ THIS IMMEDIATELY !!! Re: [oclug] Strange Fedora problem

[Jamon Camisso]

Brad Barnett wrote:
> On Thu, 03 Aug 2006 23:04:22 -0400
> Jamon Camisso <jamonation at gmail.com> wrote:
> 
>> root wrote:
>>> Hi Jamon!
>>>
>>> the matter gets worse and worse!
>>>
>>> I did what you said and now all I get is an error message that
>>> permission has been denied to create ~/.gnome2 and ~/.bash_profile
>>>
>>> So, there is no way I can get back into my user account. But, yes, I
>>> can make a new one and get into it OK.
>>>
>>> I even removed a line from my .bash_profile file which said unset
>>> USERNAME
>>> but this had no effect whatsoever!
>>>
>>> I am doing an absolute "no no" in doing this from my root but I'm not
>>> going to stay here for long! I'll create yet another user and go
>>> there!
>>>
>>> Cheers (or, not so cheery actually!)
>> If you want to keep your directory and userid, you could backup all your
>>
>> files and settings, then rm -rf $Home/* :) Careful with that one
>> though...
> 
> Be careful, Jamon says?!  Good grief, I hope so! 
> 
> 1) env variables are case sensitive with bash.  Therefore, $Home is not
> the same as $HOME, and therefore 'rm -Rf $Home/*' is interpreted as
> 'rm -Rf /*', and will delete the entire path starting at '/'. 
> Don't use env variables with rm commands, and especially with -Rf
> commands!  Env variables could be mistakenly changed, they could be
> something you do not expect!
> 
> 2) don't use env variables in examples to non-expert users, unless you
> expect those users to type verbatim what you write
> 
> 3) Croombe is likely going to use the superuser (root) account to execute
> the above command, so even if $HOME/* was used, it would delete root's
> home directory, and not the desired user's directory
> 
> 4) for crying out loud Jamon, be CAREFUL MAN!  I know you are trying to
> help, but such flippant, untested answers can destroy a person's
> data on their ENTIRE HARD DRIVE.  If Croombe simply types the command you
> have above in, he will wipe his drive.  Gone, blamo!  Again, Jamon, TAKE
> CARE WITH SUCH UNTESTED ANSWERS!

I am being. A little too cavalier perhaps, but I am being. I even 
checked with ls -la $HOME/. I mistyped $Home, my mistake. Why the 
difference between the two? What other bash variables in uppercase (the 
only ones I ever use come to think of it) have a corresponding 
*different* lowercase counterpart?