Linux - SoftwareThis forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
ok, i am running mandrake 9.1 on a dual boot system with windows95, i know the system is old, but i've invested quite a bit of time trying to get linux to work, and i don't want to give up just because i dont knwo how to get a password for a user login. i created a user account, but i don't know the syntax to user with the passwd command to either disable a password or create a password. what do i do?
ok, as i was trying to create a password for a user that i'm going to call eeee. this is what i typed in. i typed adduser just to make sure the user did actually already exist.
[root@localhost root]# adduser eeee
adduser: user eeee already exists
[root@localhost root]# passwd eeee
Changing password for user eeee
New UNIX password:
Retype new UNIX password:
passwd: user not known to the underlying authentication module
what did i do wrong? i've tried a couple of different passwords and it does the same thing. it's also kind of annoying that you cant use any word in the dictionary as a password, cause if it's something not in the dictionary i know i'm gonna forget what it is. oh well, thanks in advance for ur help,
"passwd: user not known to the underlying authentication module"
Check to see if the user is in /etc/passwd.
"it's also kind of annoying that you cant use any word in the dictionary as a password, cause if it's something not in the dictionary i know i'm gonna forget what it is. oh well, thanks in advance for ur help,"
There is an optional program that you have installed which argues with you about your passwords. I have never used it and don't remember its name. But if you throw out that program then you can use any password that you want.
"how do i check to see if the user is in /etc/passwd ?"
Open /etc/passwd in a text editor, or less. /etc/passwd has one line for each user or daemon type. The first line is always root. The first field in each /etc/passwd line is the name of the entity. So you should find a line which has the relevent user name as the first field in that line.
The fields in a /etc/passwd line are:
Sorry about that. The combination of colon-letter p comes up as a smiley.
If the password field is set to * that means that it is encrypted as a shadow password. If the password field is null that means that entity is not password protected.
The more I read this newsgroup (and ask questions here) the more I realize that there is a technogeneration gap. Sometimes I ask the same question two or three times and never get an answer because the gurus don't understand the simplicity of what I"m asking. It's almost as if they scan for keywords in my post and ignore everything __they're__ not looking for!
Don't misunderstand me steve, you have probably been the most helpful "guru" I've encountered. But if somebody say's "I'm really a newbie", do you honestly expect that person to understand:
The first field in each /etc/passwd line is the name of the entity. So you should find a line which has the relevent user name as the first field in that line.
The fields in a /etc/passwd line are:
OK, I'm stupid, right? But what is entity, uid, gid, gecos, etc...
Actually, I don't know what gecos is. I've been 'using' linux for about 6 years now. I still consider myself a newbie, cuz nobody can speak my language. I can undertand most of what you are saying, but what about somebody that installed lx first time yesterday? No hope.
thanks very much. Plz don't stop. We luv you and need you.
Distribution: RH 6.2, Gen2, Knoppix,arch, bodhi, studio, suse, mint
he just used entity to mean username.
uid userid-each userhas a number to interact with the system.
gid groupid-a group id is a number associated with a group. you can
give a broad set of rights to a user by adding them to a group that
has a certain set of rights.
i expect that i like other people that answer questions here skim the
questions, and answer what we can that doesn't take a ton of typing,
or what we can answer simply.
ok thanks, i was able to see what was in the /etc/passwd thing, and it had the name of the user. in the place where the password was supposed to be, there was an !!. when i used the command #passwd -u (username) to unlock the password, because i thought it was locked, i got this message:
Segmentation fault (core dumped). what does this mean?
When Unix first began to spread beyond AT&T, General Electric wrote an Unix operating system called GECOS. Some long forgotten specialized field was inserted into /etc/passwd for GECOS to use. GE sold their computer division to Honeywell about 1970 and Honeywell sold GECOS for a while. GECOS died a well deserved death about 25 years ago but the gecos field marches on!
"I realize that there is a technogeneration gap."
Yes. I sometimes find that I answered a different question than was asked. I also have the problem that my Linux knowledge is self taught. I often think of Linux in terminology used on operating systems that I have worked on in the past but is confusing to a Windows/Linux person. I also occasionaly get somebody reinterpreting what I say so that it makes sense to other people. This is fine with me and I appreciate the help.
"where the password was supposed to be, there was an !!. when i used the command #passwd -u (username) to unlock the password, because i thought it was locked, i got this message:
Segmentation fault (core dumped). what does this mean?"
The command that you were using failed, probably because of screwed up data in /etc/passwd. The first thing you should do is straighten out /etc/passwd. Do not edit /etc/passwd directly since a simple edit error can make Linux unusable. Use the commands that trickykid listed to work with your problem. After you use each command then check /etc/passwd to see what that command really did. The line with !! obviously contains garbage. See if you can use one of trickykid's commands to delete that line entirely. Be careful and read the man page thoroughly before you use any command. It is possible to delete the /home/user tree as well as the errant line in /etc/passwd. Once you get the garbage out of /etc/passwd then you can rebuild your users, groups, and passwords the way that you want.
ok, thanks. i also have another question, i think i have games installed on my computer, and when i was looking at the file in /etc/passwd there was a games user with an * in the passwd spot. in the man file for passwd it said an * means the password is encoded. how do i uncode it? there was a command, but i'm afraid to use anything i don't totally understand because i didnt want to mess anything up. do i have to sign in under the games user to access the games, or can i run the programs through root or a user account after i get it setup? thanks in advance for ur help.
"how do i uncode it? there was a command, but i'm afraid to use anything i don't totally understand"
You cannot uncode the password. It is part of UNIX security that even root cannot find out other peoples passwords. If root wants to she can change a user's password to a new password without knowing what the old password was but she cannot read the old password. So when a user loses her password she tells root. Root supplies the user with a new password, then user logs on and then changes her password to a new one that root doesn't know. If you lose root's password then it's exciting times.
"do i have to sign in under the games user to access the games"
The first field in each entry in /etc/passwd is called username. Actually most of these entities (I don't have a thesaurus handy so I'll risk another uproar over entities) are not user names. They are a mechanism whereby a user process can obtain root privileges. For example: Suppose you are using kpackage, or the Mandrakes rpm installer whatever it is called, as a user to install rpm packages. The rpm installer needs root privileges so it asks you for the root password. The rpm line in /etc/passwd is part of the mechanism used for the installer to pass the root password to pam (the security routines) and for pam to give the installer root privileges which cannot be passed on to other programs in user space. There is no user named rpm and you cannot sign in as rpm.
The games entry works similarly, except that I do not know exactly why games need root privileges. Perhaps it is so that they can drive the video card faster. In any case you probably do not have a user called games on your machine. But it is possible for you to run a game as user which needs root privileges. In which case the game will ask you for the root password.