Anything related with user accounts and user management on Unix-like systems.
11
votes
1answer
951 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 ...
8
votes
2answers
2k views
How to apply changes of newly added user groups without needing to reboot?
Assume I'm logged in with user takpar:
takpar@skyspace:/$
As root, I've added takpar as a member of group webdev using:
# usermod -a -G webdev takpar
But it seems it has not been applied. because ...
5
votes
2answers
997 views
How to restrict internet access for a particular user on the lan using iptables in Linux
Let's say there are two users on the LAN, A and B. How do I restrict user A from internet access using iptables rules and saving the rules so that after reboot, they are still effective. And suppose I ...
10
votes
11answers
903 views
Concern about logging in as root overrated?
For personal linux on my personal notebooks, I've usually set my environment to autologin as root even under X or lower runlevels. I've found my workflow is very pleasant and fast, without any ...
20
votes
6answers
8k views
How do you kick a benign user off your system?
I was googling this a bit ago and noticed a couple of ways, but I'm guessing that google doesn't know all. So how do you kick users off your Linux box? also how do you go about seeing they are logged ...
7
votes
1answer
421 views
Lightweight virtualization on Linux with user isolation
What Linux-on-Linux virtualization technologies provide user isolation? Specifically, I want root in the virtual machine not to have any privilege on the host.
This was not the case for LXC, but was ...
7
votes
3answers
438 views
Does character 'ä' in usernames cause bugs in linux systems?
I want to use my first name as an username but it contains character 'ä'.
I found this thread.
Now I understand, why some some characters are disabled, but what about 'ä'? Can this character cause ...
6
votes
7answers
960 views
Is it bad practice to set root's shell to something other than the default?
Once a friend of mine (who is an experienced Unix/Linux user) told me that setting root's shell to something other than sh (i.e bash or zsh) might create problems, because some script might assume ...
21
votes
3answers
6k views
Disable a user's login without disabling the account
Let's say I create a user named "bogus" using the adduser command. How can I make sure this user will NOT be a viable login option, without disabling the account. In short, I want the account to be ...
12
votes
3answers
766 views
Can I limit a user (and their apps) to one network interface?
As the title really. I've actually got two scenarios to apply this:
Multiseat Desktop: two network connections both with internet gateways and two accounts doing bandwidth-intensive tasks on each. I ...
6
votes
2answers
3k views
GID, current, primary, supplementary, effective and real group IDs?
The following links discuss these concepts in different contexts. I have read their definitions, but I still can't tell how they are related, or if some of them are just the same.
Current group ID
...
4
votes
2answers
10k 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 ...
9
votes
2answers
4k views
How to create a user with limited RAM usage?
So I have 4 GB RAM + 4GB swap. I want to create a user with limited ram and swap: 3 GB RAM and 1 GB swap. Is such thing possible? Is it possible to start applications with limited RAM and swap ...
8
votes
2answers
3k views
How can I determine if someone's SSH key contains an empty passphrase?
Some of my Linux & FreeBSD systems have dozens of users. Staff will use these "ssh gateway" nodes to SSH into other internal servers.
We're concerned that some of these people use an unencrypted ...
6
votes
2answers
2k views
Why is sudo telling me my password is wrong?
I recently installed OpenBSD 4.9 in my computer, so I could learn a little bit about Unix-like operating systems. I added a new user to the system called bruno. Ok. When I use the 'sudo' command, it ...
3
votes
3answers
370 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?
1
vote
2answers
56 views
Changing username but not home directory
Is it a bad idea to do usermod -l login-name old-name to change my username while leaving my home directory name intact?
A few years ago my university changed my username, but since it didn't affect ...
1
vote
1answer
1k views
switching from user to root and revers (freebsd)
i want to make some modificaciones with root and then with my user, in fact i want to install sudo and he give me the error in the first step:
cd /usr/ports/security/sudo
make install clean
...
1
vote
1answer
200 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 ...
5
votes
1answer
555 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 ...
4
votes
1answer
995 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 ...
3
votes
2answers
274 views
A question about permissions of hierarchical directories
I have some directories, with following permissions:
drwxr-xr-x 18 user1 root 4096 Oct 27 11:25 /home/test1/test2
drwxr-xr-x 24 user1 root 4096 Oct 21 08:38 /home/test1
drwxr-xr-x 492 root root 12288 ...
3
votes
1answer
768 views
User logged in by sftp does not show up in `w`
My server is Centos 5. I have a chroot environment set up with the following in my sshd_config
Match group sftponly
ForceCommand internal-sftp
ChrootDirectory %h
AllowTcpForwarding no
...
3
votes
3answers
2k 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?
2
votes
4answers
289 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 ...
1
vote
1answer
242 views
Is there a shorter way to change username, home directory and move files at the same time
I wanted to use and have tried
sudo usermod durrantm_test -mdl durrantm_test2
but I get
Usage: usermod [options] LOGIN
...
However
sudo usermod durrantm_test -l durrantm_test2 -md ...
1
vote
2answers
109 views
How would you create a user with the HOME_DIR field in /etc/passwd completely blank?
Closest I can come is:
useradd --home / -r --shell /sbin/nologin someuser
But this creates an entry into /etc/htpasswd that looks something like this:
someuser:x:100:100::/:/sbin/nologin
I want ...
