If shadow file no permissions, Owner & Group owner also a root,but how it can update if another user change its password and that user unable to login shadow file

The passwd utility, /usr/bin/passwd, has this permission mask:
That "rws" is the so-called super-user bit turned on, meaning that any user executing it has, for the duration of the execution, root's permissions; the two x's mean that anybody can execute the utility. So, "you" or "anybody else" can execute the passwd utility and will be able to change their own password (root can change anybody's password but a user can only change their own).

The file /etc/shadow mask is
which means that only root can write to it, the x means that only the shadow group can read from it and there is no public access at all; i.e., "you" cannot see its content.

The passwd utility is written so that the only thing a user can do with it is change their own password but can't fiddle with anything else (the utility "knows" who you are when you execute it, by your numeric user identification number, your UID, which is the third field on the line in /etec/passwd; if your UID is not zero, you're not root and you're restricted as to what you can and cannot do).

That's pretty much that.

Hope this helps some.

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1.If Windows is server and Linux as client then can we share the files

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if we enter in to ftp> then what command is used to come from directory

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Anybody send me Linux Interview questions

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Yes, and this question has been asked/answered on this site MANY times. That's what Samba is for, letting Linux and Windows systems share files.
No idea what you're asking. Doing a "dir" is the first answer that comes to mind, but you could also type in "help", and get a list of commands yourself...perhaps, look them up???
No. First, because there's NO WAY anyone can know what you're going to get asked on an interview. Second, if you don't know the answers to the questions on your own, you're not qualified to have the job. If you want to know the answers for a 'Linux interview', then learn Linux first.

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What is the difference between /home & /localusr directories?

---------- Post added 12-05-11 at 12:28 AM ----------

What is difference between systemuser & Normaluser?

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/home is a default(not always) home directory for all user in unix based machine. while /localusr is package dependent, not all unix machines will have this directory.

"systemuser & Normaluser " these notations also package/distribution dependent.

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Sorry, but these are not correct answers.

/home *USUALLY* is the location where home directories for users are created. However, the partition can be named ANYTHING, and the users home directories can be ANYWHERE, so this is a guideline, not an absolute. There is no /localusr directory on most installations...but if you mean /usr/local, that's where some shared files that you want users to be able to read/execute (but not necessarily write) are stored.

System users are built for system services...things like FTP users, NFS users, etc., that need to be present for a service to run, but don't have a person associated with them, and don't need to ever log in. "Normal" users are just that...regular users that are set up to use the system.

Again, OP...you need to try to look these things up. All of your questions thus far sound like homework, and you need to show some effort to answer them on your own.

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Per the LQ Rules, please do not post homework assignments verbatim. We're happy to assist if you have specific questions or have hit a stumbling point, however. Let us know what you've already tried and what references you have used (including class notes, books, and Google searches) and we'll do our best to help. Also, keep in mind that your instructor might also be an LQ member.

I kindly invite other members to avoid posting answers, until the OP demonstrates a good commitment and provides some feedback. Thank you.

My intention also the same.

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Then you should have stated it as a guideline/intention, rather than a concrete answer.

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After getting the Answers I'm not getting clarity What is the difference between /home & /localusr directories?Can anybody explain what is /home & /localusr

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Shravan kumar,

You keep asking the same questions repeatedly , even though few Senior Members and Gurus gave you some answers and advised you to find the information on your own.(Because the questions which you ask are very basic questions)

This website is not for providing Linux Training/Courses. If you really want to learn Linux then I strongly suggest you to use Basic Linux books or guides available online.

As a member of LQ , we should adhere to LQ Rules.

Here are some books and guides which can help you learn Basics of Linux Operating System.

http://tldp.org/LDP/intro-linux/html/

http://www.linuxhomenetworking.com/

http://www.linux-tutorial.info/modul...ent&pageid=224

I think he has been posting questions in right forum - newbie.

I am all for asking questions - no discouraging of any kind - BUT - Misuse of "helping" spirit/willingness to assist - should not be extended beyond whats needed - unless "commitment" and "feedback" are apparent