Thank you very much for this very clear explaination. Denis Basil Fowler dixit: > You have confused the two commands. > > su means "switch user" Let us assume that you have three users alpha, bravo > and root. Let us assume for the moment that you are logged in as user alpha > and alpha's password is ahpla. Let us also assume that the password for bravo > is ovarb, and the password for root is master. I know that these passwords are > ridiculous, but this is for example. > > I know that you are using a Debian based distro (Ubuntu) because you are > invoking the apt-get command. In such distros the first user alpha is set up > as a master user account and often the root account is disabled. This is good > for single user machines, but is a PITA for multiuser setups. > > When you use su, if it has no arguments, it assumes that you wish to invoke > the root account and will demand Root account's password (in this case MASTER) > If you follow su with an account name (such as bravo) will will be prompted > for bravo's password (in this case ovarb). When the correct password for the > TARGET account is entered, you will then be running as the target account (to > leave, type 'exit' or control-d) > > Now, with distros such as Ubuntu, the root account is disabled, so su does not > work. A correct password (equivalent to MASTER) does not exist. You have to > type in sudo su. You then will have a root shell, and you can run "make > aptget". > > sudo is a program that is designed to solve a difficult administrative > problem. How do you give an ordinary user power to perform an action (such as > managing printers) that normally requires root privileges without giving him > /her complete control over the machine? > > Sudo looks up a special file - readable only by root - /etc/sudoers, which > lists who can do what under which conditions, and allows or denies the desired > action accordingly. > > In the case of Ubuntu, the /etc/sudoers file states that the first user > (alpha) is given permission to do anything provided that ALPHA's password is > entered, and everyone else (bravo) nothing. > > To modify the /etc/sudoers file a special editor (visudo) is used, because any > error in the format of the file will block sudo - this is intentional. > > To activate the root account - not to be done unless you know what you are > doing, the /etc/passwd file has to be modified. A root password will have to > be created, and the shell command (usually /bin/false) changed to /bin/bash. > > RedHat based distros such as Mandriva have a separate root password at > installation, and each user has a separate password. They use kdesu and su. > Sudo has to specially downloaded, because it is only needed in exceptional > cases. > > Hope this helps. > > Basil Fowler > > > > On Thursday 24 Dec 2009 08:35:24 spir wrote: > > Hello, > > > > I'm aware this question is ~ OT, not really kde related, but have no idea > > where else to post it, and surely many people here know the answer. To > > install new software (actually, the language Io, for which there seems to > > be no package), I had to type: > > > > su -c "sudo make aptget" > > > > This will not work. I'm asked for a password, then get "su: Authentication > > failure". Well, this simply cannot be, for I have only one admin password > > AFAIK and it works fine for sudo and kdesudo. I tried an old password I > > had long time ago (changed to make it more difficult), in case the one for > > 'su' may have sticked to old times while the one for sudo has changed, but > > it is not accepted neither. > > > > I take the opportunity to ask about the use of 'su' in a normal user > > session. Also, is there another way to perform the above action? > > > > Denis > > ________________________________ > > > > la vita e estrany > > > > http://spir.wikidot.com/ > > ___________________________________________________ > > This message is from the kde mailing list. > > Account management: https://mail.kde.org/mailman/listinfo/kde. > > Archives: http://lists.kde.org/. > > More info: http://www.kde.org/faq.html. > > > ___________________________________________________ > This message is from the kde mailing list. > Account management: https://mail.kde.org/mailman/listinfo/kde. > Archives: http://lists.kde.org/. > More info: http://www.kde.org/faq.html. > ________________________________ la vita e estrany http://spir.wikidot.com/ ___________________________________________________ This message is from the kde mailing list. Account management: https://mail.kde.org/mailman/listinfo/kde. Archives: http://lists.kde.org/. More info: http://www.kde.org/faq.html.