Anything related with user accounts and user management on Unix-like systems.

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8
votes
5answers
4k views

Can I allow a non-root user to log in when /etc/nologin exists?

Suppose a non-root user with sudo privileges executes a delayed shutdown (shutdown +10 or whatever) and logs out. Then, before the shutdown occurs, he wants to log back in and cancel the shutdown. The ...
5
votes
4answers
1k views

How sudo/root-ness detection works

Programs that make changes system-wide require sudo unless I am already the root user. Now, the question is: how exactly does the system figure out that I am (not) root? Does it: Check to see if ...
3
votes
1answer
279 views

Duplicate a user, or at least the password

I have some application that needs to create users that have the same password as others. Is there a way to do this without having to edit the /etc/shadow manually? Some sort of command?
2
votes
1answer
361 views

Verify that /etc/passwd has correct number of fields on each line?

I'm looking for an easy, portable way to validate the number of fields in /etc/passwd, /etc/shadow, /etc/group and /etc/master.passwd. This would run on FreeBSD, Linux and other Un*xes. pwck does ...
8
votes
2answers
10k views

How can I create users with only remote ftp access on Linux server?

I'm running a Ubuntu 10.04 LTS server and I want to create users who can only access the server from FTP. What I did so far is: Install vsftpd Create new user with default login shell set to ...
4
votes
1answer
635 views

Why do I need to use newgrp or su (or logout and login again) to have new group memberships applied?

What is it that makes new group membership require a new login (or new login shell as started by su or newgrp) to be visible? Just running another bash (or whatever other shell) instance with --login ...
12
votes
2answers
38k views

How to add a ssh user who only has permissions to access specific folder?

How to add an ssh user who only has permissions to access specific folder? useradd -d /var/www/xyz.com.tr/musteri -s /bin/bash -g sshd musteri I created a user called musteri. I set its home ...
2
votes
2answers
173 views

How to create a new user without his own FS but with access to write to only one folder of user that creates him?

What are the command(s) to create a new user (not from su), give him the ability to write to only one folder which is some directory owned by an already existing user (the one that created him)? ...
2
votes
1answer
231 views

'who' has no output

I'm new to Arch Linux, and I just built my system up. But when I ran who in urxvt, I got nothing. Anyone know what's going on? BTW. I use Slim + OpenBox. And here are parts of my configure files. ...
9
votes
1answer
10k views

Mounting an ext3 fs with user privledges

I'm trying to mount an ext3 file system from another linux installation so that the user, not root, will have full access to all the files. (I really do need user to have access to those files, ...
4
votes
2answers
12k views

How do I log out of all my active sessions?

For some reason, I have a few open sessions on an SSH server that I don't know about. I assume they're leftovers from when my pipe broke. $ users user1 user2 user3 me me me me Is there a way to log ...
13
votes
6answers
11k views

What does the “number” in the owner field of files signify in linux?

I copied many files to my new linux host. I see that all files have the owner and group both set to 515. What does that mean?
2
votes
2answers
2k views

SFTP with Mysql user pass instead of PAM

Is there a way for people to log onto a debian server via sftp using just mysql database table as authentaction. IE not adding a user to the system? I know it can be done over ftp and TLS but i ...
2
votes
2answers
307 views

using chown in linux

I want to assign www-data user full rights in folder /var/www/ and all of the files inside this folder. I have tried chown www-data /var/www/
1
vote
1answer
68 views

Equivalent of newusers for groups

The newusers command is useful for adding or modifying users in bulk. Is there an equivalent command for managing groups?
10
votes
3answers
5k views

What is the point of the 'operator' user?

Many un*x systems ship with a user account named 'operator'. What is the purpose of this account? Do some systems actually make use of this account, or is this more of a historical legacy? Have you ...
3
votes
4answers
2k views

different shell for root and non-root user

When I ssh as root, my shell is bash, but when it's a non-root user it is sh. How can I make them both to use bash? This actually goes against the logic in this question: Why root's default shell is ...
7
votes
2answers
8k views

What are the allowed group names for groupadd?

I followed these instructions to build Shadow, which provides the groupadd command. I am now getting an error when trying this: $ groupadd automake1.10 groupadd: 'automake1.10' is not a valid group ...
6
votes
1answer
1k views

How to get the name of the user that launched `sudo`

My problem: I have a Python program, and the user launch it using sudo. Sometimes I have to get the user's home, and I can do this only knowing its name: import pwd pwd.getpwnam(username) So: how ...
6
votes
2answers
416 views

Using NIS without NFS

I'm configuring several computers in a lab to operate with the same login credentials shared between the computers, but without sharing the home directories. I'm considering using NIS for sharing the ...
3
votes
4answers
3k views

How to configure permissions to allow file access?

I'm running Wowza Media Server on my server as "root". The problem is that all files created (recorded) by Wowza are "root:root" and aren't writable, editable, or deletable by any other users. How can ...
2
votes
2answers
8k views

How can I switch one user to another in Freebsd?

How can I switch one user to another in Freebsd? For examples, I am user david now and I want to change to user Bob. This is a personal OS for my study. not a server. I searched it, but only got ...
5
votes
1answer
7k views

What is hvc0? (appearing in “who” list)

I have an Ubuntu Server, and when I type who, to see who's connected, I can see that there's a user connected, and instead of being logged to a pts/x, he's connected to hvc0. Is there something to ...
5
votes
2answers
8k views

How do I give all the permissions to a file for a single user that's not me?

When I want to grant access to another user to my file, I use chmod 777 file, but if I want to be sure I'm granting permission just for that user, how can I do it? -- update The file is owned by ...
7
votes
4answers
371 views

How can I safely give a shell to somebody?

I have a question about giving a shell account to somebody. How safe is it? He could read /etc. How can I give a secured shell account that will only restrict the user to some bins and his own home? ...
3
votes
3answers
8k views

Why is file ownership inconsistent between two systems mounting the same NFS share?

I have one IBM AIX server (serverA) which is connected to the san storage. I have created a volume group and also file system (jfs2) and mounted to directory /profit. After that I created a NFS ...
4
votes
3answers
4k views

How to find the machine from which a user logged into current machine using ssh?

In a multi server architecture, is it possible to find out from which machine a user logged into current machine using ssh? For example, user1 logged into host1. From there, the user logged into ...
3
votes
3answers
3k views

Reset all groups to default

I recently set up some groups and users on my machine, and now I want to remove all those users and all those groups. Somewhat stupidly, I read on an Ubuntu forum or something like that that it was ...
7
votes
1answer
3k views

Why can't I use arrow keys in terminal on Debian 6? (nonroot)

When I am on a non-root user I cannot use ↑/↓ to list my previous commands, and if I am typing I can't use ←/→ to say, add in a directory or to correct the ...
2
votes
1answer
5k views

How do I add a new user to an embedded Linux system by hand?

I have a system which was designed for use by root only and I want to run an FTP server on it. The software I use handles authentication by using same username and password as OS itself. To me it ...
3
votes
2answers
1k views

How to trace a process to original user?

Say, on a Solaris server, user1 logs in, switches to someother user, say sruser, using su - and then starts a process of id X. And then another user user2 logs in, switches to sruser the same way and ...
4
votes
1answer
785 views

How to disable certain system calls for a given user?

I am creating a web app similar to codepad and for each run-action my app copies a directory (/home/radeks/voidptr/private/chroot-root) to /tmp/voidptr/[random-id]/chroot-root. This chroot directory ...
2
votes
2answers
2k views

How to get hashed password in /etc/shadow using getpwnam()?

Apparently there is a function (getpwnam) that given a username, will return the appropriate entry in /etc/passwd with the other details for that user (shell, uid, gid, etc.). However, I have no idea ...
6
votes
2answers
8k views

Add all users in one group to another group?

I have some users in a group called aa and I need to give them the rights to write to a folder which is currently tomcat:tomcatdeploy. The straightforward way to do this is to add all the users to ...
7
votes
1answer
1k views

Why root's default shell is configured differently with other normal user account's default shell?

As I know, root's default shell is configured csh and normal user's default shell is sh in FreeBSD. And in Ubuntu, root is dash, normal user is bash. (refer: What's the Ubuntu's default shell?) Why ...
8
votes
4answers
3k views

Multiple Users on a Desktop Environment [closed]

This is probably a REALLY stupid question. But anyways, lets pretend we had a *nix rather powerful system... Now Obviously I know you can set up multiple users to login to a system.......but how ...
2
votes
3answers
929 views

su and aliases confusion

I create an alias as my current user in the bash shell, which I can see using the alias command. When I switch user without the -, i.e. su testuser, the alias is not carried into the new user's ...
21
votes
6answers
21k views

How do I completely disable an account?

How do I completely disable an account? passwd -l will not allow anyone to log into an account using a password but you can still log in via private/public keys. How would I disable the account ...
2
votes
3answers
301 views

How to make files created by a specific user to have specific permissions by default

Here's a sequence of commands and the resulting output: $ touch testfile $ stat -c'%a %A' testfile 644 -rw-r--r-- What must I do so that when a user follows that sequence, I get this output ...
4
votes
4answers
5k views

NIS: How to allow access to both local and remote users' home directories?

We have a NIS server with shared users' home directories in '/home'. We're used to mounting the server's '/home' using '/home' as the mount point on each NIS client. However, if we do this with a ...
13
votes
3answers
6k views

How can I make a user able to log in with ssh keys but not with a password?

I would like to create a user and have no password. As in you cant log in with a password. I want to add keys to its authorized_keys by using root. This is for my automated backup system.
3
votes
1answer
808 views

Set visible directories for SFTP access?

I am setting up SFTP access to one of my machines running Linux with the Dropbear SSH server. When I SFTP onto the machine remotely, I can see the entire filesystem on it, even if I might not have ...
2
votes
1answer
123 views

rc control user

I am playing around with rc scripts. I am starting a daemon from rc.local. I would like to know how I start the process under a specific user instead of root?
4
votes
4answers
272 views

How do I check what 'normal' users are there on the system?

I want to find out what 'normal' users are available on a system. By normal, I mean those who are manually created, not those like sshd or gdm.
7
votes
3answers
3k views

Once sudo su'd to root, is there a command to see my username?

I have sudo rights on a redhat box; once I've sudo su - to become root in a shell, are there any commands I can run to see what username I su'd FROM?
6
votes
3answers
8k views

Why are underscores not allowed in usernames in some distros (Debian for example)

So why has the underscore been considered a bad character for user names in Debian (and possibly other distributions) while it has been removed from adduser's NAME_REGEX in Ubuntu?
8
votes
2answers
8k views

I added a user to a group, but group permissions on files still have no effect

I changed permissions of a file (chmod g+w testfile) and running ls -l testfile gives: -rwxrwxr-x 1 user1 user1 0 2011-01-24 20:36 testfile I then added a user to that group ("/etc/group" has ...
3
votes
2answers
1k views

PHP interface to manage linux user accounts

I have a linux web & samba server. I need to give administrators access to manage minor accounts & groups. Is there a secure php web interface that can do this? I don't want to give them shell ...
5
votes
3answers
526 views

Unix users, groups, and permissions

I don't understand unix users, groups, permissions, etc. For example, things managed by the chmod, chgrp, usermod, groupadd, etc. commands. How do all these things work?
15
votes
1answer
3k views

Can one PC be used by two users at the same time via dual-monitor?

Since modern PCs can use two screens at the same time I wonder if it is possible to plug in two keyboards and mouses as well to have the two screens run two (more or less) independent X-sessions at ...