su root = BIG BAD OOPS!

[cindybubbles]

Back in university, I was studying the basics of Unix. I was getting to the point where I had to practice using the statement "su root".

For those of you who don't know this, "su root" means that you are trying to gain super user access as the administrator (root). I was going to go through the exercises as prescribed in my textbook.

There was, however, one BIG problem. I was not at home; I was using the school's lab computers where we already had an admin. I type in "su root" and I got "Access Denied". I tried again, and again, and again.

The next time I tried to log in, I was LOCKED OUT!

I had no idea what went wrong, so I went to the admin. Guess what she said?

Admin: Why were you trying to be "su root"?

I explained my course requirements, and she said that "su root" gives the user admin access, which is a threat to the school system if you don't know what you're doing!

Fortunately for me, she restored my access, as long as I never used that statement in the school labs ever again!

[klhanson]

nowadays this is where virtual machines come in handy!

[csquared]

su - -c "rm -rf /" = REALLY REALLY BAD

Do not try this at home, or anywhere else for that matter.

[dalesys]

su - -c "rm -rf /" = REALLY REALLY BAD

Do not try this at home, or anywhere else for that matter.

You will have Wile E. Coyote's expression... as he's trying to hang onto the thin thin air.

[pzychobitch]

su - -c "rm -rf /" = REALLY REALLY BAD

Do not try this at home, or anywhere else for that matter.

...why not?

[Racket_Man]

...why not?

If memory serves me correctly su give you super user or root access and the rm -rf (remove command and I do not rememeber the switches meaning but I do know they are bad) deletes ALL files in the system from the root directory out protected or not.

In other words delete ALL files (command, data, bin, etc) wiping the file system clean.

the normal operation of the rm -rf command would to be delete all of the files in the users home directory or whatever driectory you are currently in (I think)

[csquared]

If memory serves me correctly

Your memory is pretty good.
-r Recursive
-f Force

And for anyone who has tried it, you know that it usually won't wipe out the entire system. The system will typically crash (after removing a critical file) long before the command can complete.

[lordlundar]

Your memory is pretty good.
-r Recursive
-f Force

And for anyone who has tried it, you know that it usually won't wipe out the entire system. The system will typically crash (after removing a critical file) long before the command can complete.

Of course, by that point you're hosed anyway.

[csquared]

Of course, by that point you're hosed anyway.

By that point, you have to ask "How good are your backups?"

One of the many reasons users get in trouble when the try to use "su root" and other variations.

[artcurmudgeon]

As a former linux admin, my only comment on this is,,,

Unix is proof that the almighty wanted to come up with a process of weeding out those who should never ever touch a system, let alone have any rights to it....

...And low the admins were pleased...

Yes, I am being a smartarse!

[dalesys]

Unix: n. PeopleOS who have had a eunique experience, vs. the removal of important parts needed for social interaction.

[csquared]

If we are going to go there...

Dilbert

[Chromatix]

Your memory is pretty good.
-r Recursive
-f Force

And for anyone who has tried it, you know that it usually won't wipe out the entire system. The system will typically crash (after removing a critical file) long before the command can complete.

On Linux at least, it can and will. Once loaded into RAM, the command can survive the unlinking of it's backing files (the files still exist, becoming "orphans" and are actually deleted once all processes using them have closed).

Even so, I am very surprised that you are being taught about "su" without first being taught about the pitfalls of "rm" - especially that specific pitfall.

[Racket_Man]

Your memory is pretty good.
-r Recursive
-f Force

And for anyone who has tried it, you know that it usually won't wipe out the entire system. The system will typically crash (after removing a critical file) long before the command can complete.

I thought I was on the right track (no Googling just memory). I did a little tech support on IBM AIX on the RS6000 processors (went through several OS and hardware classes) about 12 years ago. that is how I remember the su and rm commands and what was bad about them if you were not very CAREFULL in their execution

[roxtar]

another fun one is chmod -R 000 /

ACCESS DENIED
ACCESS DENIED
ACCESS DENIED