root ,sudo !!

MTK358 · 10-21-2011, 03:06 PM

Quote:

Originally Posted by Cultist

um, isn't it short for superuser?

No, since you can use it to switch to any user account.

thezerodragon · 10-21-2011, 03:30 PM

Quote:

um, isn't it short for superuser?

No, as we were discussing, this command substitutes the user. As acid_kewpie explained, the verbose form would be

Code:

su --login

When left blank, the shell assumes you mean root or superuser. But you could just as well type in, say

Code:

su --login billy

and log in as username billy if such a user existed. Thus su can't be assumed to stand for SuperUser.

cynwulf · 10-21-2011, 03:55 PM

Quote:

Originally Posted by Cultist

um, isn't it short for superuser?

It's short for "substitute user" (no arguments to become a superuser).

Man pages tend to differ.

frankbell · 10-21-2011, 09:07 PM

Quote:

Originally Posted by Cultist

um, isn't it short for superuser?

No, though I thought so for a long time myself.

If you don't specify a user name, su assumes root, but if you enter "su joeblow" and follow it with joeblow's password, you will be su-ed as joeblow.

jlinkels · 10-21-2011, 09:22 PM

Quote:

Originally Posted by frankbell

If you don't specify a user name, su assumes root, but if you enter "su joeblow" and follow it with joeblow's password, you will be su-ed as joeblow.

It is even better. When you first su to become root and then su joeblow you don't need joeblow's password. Very handy when you want to research permission problems (or whatever in fact). You can become a user and act like him without having to ask his password.

sudo su joeblow does the same trick.

jlinkels

thezerodragon · 10-21-2011, 11:28 PM

Quote:

It is even better.

cool, this info was really useful.

shanky · 10-22-2011, 04:25 AM

Thanks..i got to know a lot ..but was confusing in the beginning..thanks again !!

acid_kewpie · 10-22-2011, 04:45 AM

Quote:

Originally Posted by jlinkels

It is even better. When you first su to become root and then su joeblow you don't need joeblow's password. Very handy when you want to research permission problems (or whatever in fact). You can become a user and act like him without having to ask his password.

sudo su joeblow does the same trick.

jlinkels

I wouldn't count this as specifically interesting, just logical given the status of the root account. running su inside of sudo should be punishable by death IMHO though. "sudo -i -u joeblow" would be a much better way to do it for various reasons. Given a correct sudoers setup that is.