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

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14
votes
2answers
14k 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 ...
7
votes
3answers
20k views

How to create an unprivileged user in CentOS?

I want to create an unprivileged user to run my RhodeCode server and Celery daemon on a CentOS instance. I think the accepted definition of this is no home directory, login disabled, and no shell ...
22
votes
6answers
68k views

How can I look up a username by id in linux?

The command id can be used to look up a user's uid, for example: $ id -u ubuntu 1000 Is there a command to lookup up a username from a uid? I realize this can be done by looking at the /etc/passwd ...
15
votes
3answers
2k 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 ...
12
votes
3answers
18k views

Allow user1 to “su - user2” without password

I need to allow user martin to switch to user martin-test without password su - martin-test I think this can be configured in /etc/pam.d/su. There are already some lines in that file which can be ...
20
votes
8answers
22k views

How do you create a user with no password?

In os X it's possible to have users without passwords. If you inspect them with dscl their password show up as *. This is used for system users such as users for databases like mysql, pgsql etc. ...
17
votes
1answer
24k views

How do I set the user of php-fpm to be php-user instead of www-data?

I am using php-fpm on debian with nginx for php5 support. I would like to have php-fpm to be under the user&group php-user instead of www-data. I thought the init.d script would have the user ...
16
votes
2answers
9k views

How do I leave a message for another (local) user?

I know you can use write to send a message to a currently logged in user, but how do you leave a message for a user who is not logged in? The solution I have seen is modify the motd, but that will be ...
9
votes
1answer
11k 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, ...
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?
19
votes
5answers
1k views

Find files that a user can write, efficiently with minimal process creation

I am root. I would like to know whether a non-root user has write access to some files - thousands of them. How to do it efficiently while avoiding process creation?
7
votes
2answers
9k views

How to grant non-root user access to device files

I have device file that appears in /dev when a specific board is plugged in. The read and write operations to it work just fine, but in order to open the device file the program needs to be executed ...
6
votes
2answers
1k views

Deleting users with nologin shell

On a security audit performed on our production Linux servers , we were asked to remove nobody user if no application are using it. I checked and could see that there are no files owned by 'nobody' ...
6
votes
2answers
9k 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 ...
5
votes
2answers
5k views

Disk usage summary per user

Is there a way to get the disk usage per user under a given path? du doesn't seem to have an option to aggregate disk usage per user, and df only seems to report how much disk is left on the drive. ...
4
votes
2answers
1k views

How to see who is logged on to many workstations?

Before I go to work creating my own I would like to find an existing system to do the following: Provide a concise list of users logged on to any of the workstations Show workstation host name, IP, ...
4
votes
1answer
641 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 ...
2
votes
2answers
1k views

Create guest account with restricted access to applications

I'm trying to create a guest account in arch linux that only allows the user to use simple applications like firefox. I do not want them to have access to programs like terminal or grub-customizer ...
2
votes
3answers
14k views

Get environment variable of other user [closed]

Is there a way I can see the environment variable of an other user? I want to do that as root, so permissions won't be a problem I guess. For the user himself, I use echo $PATH or set | grep PATH ...
7
votes
2answers
6k 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 ...
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 ...
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
2answers
2k views

How can I start a 'screen' session as non-root user

Is there a way I can open a new 'screen' session on my RHEL box as a non-root user? When I try to open a new screen using the 'screen' command as a non-root user, it fails and I get the following ...
5
votes
3answers
3k views

Restrict user access in linux

I'm creating a new user with the following details: useradd -d /var/www/html/testuser.com -G users testuser I proceed by creating a new password for the user and attempt to login via SSH, I land on ...
4
votes
2answers
129 views

Fully seperate two accounts without installing seperate operating systems?

Our class is finally installing Mint Linux on our machines. The problem is our teacher is scared that we'll play war games against the two classes that use the computers. His solution is to install ...
2
votes
0answers
275 views

User Acces restrict to only one folder

I am trying to establsih SFTP User rights at a server to only one folder, following the guidelines here: ...
2
votes
1answer
368 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 ...
1
vote
1answer
1k views

How to copy files as Jenkins “post build” action if i don't have privileges to destination directory

I have the following users "architecture" : root access is disabled. admin user have access only to its home directory. Apache runs as root service (root is the only one that have access to ...
1
vote
2answers
473 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
11k views

switching from user to root and revers (FreeBSD)

I want to make some modification 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 ...
0
votes
1answer
11k views

SCP without password prompt using different username [duplicate]

I have 2 servers, Server1 and Server2. On Server1 I have a user named user1. On Server2 I have the user named user2. I need to be able to write a script that runs on Server1, which will scp some ...
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 ...
5
votes
2answers
557 views

How to control the time that users spend on

I need a solution that allows me to control the time that each user spend on the computer, excluding idle time (some kind of parental control). I've tried timekpr, but it doesn't work on Ubuntu 13.10. ...
4
votes
2answers
425 views

Why are newly created users assigned to primary groups of their usernames?

I've noticed that on a number of linux distributions that whenever a new user is created, it is assigned to a primary group of its own name. eg. If i create a user called "testuser", by default it is ...
4
votes
2answers
488 views

Understanding getlogin()

I think the previous iteration of this question was a little bit like a carpet bomb of questions, so that may have turned people off to it (to the point of almost being flagged for removal) so I'll ...
4
votes
4answers
12k views

What type of permissions should a user's home directory and files have?

I'm working with a fresh install of Ubuntu 12.04 and I've just added a new user: useradd -m testuser I thought that the -m flag to create a home directory for users was pretty standard, but now ...
3
votes
2answers
1k 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
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 ...
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 ...
2
votes
2answers
56 views

When opening a terminal does not require a login?

Speaking about Linux and in particular Ubuntu (from 14.04) systems: Case 1 - As pointed out in this answer, processes that allocate a pseudo-terminal don't need to make a login: for example, cups. ...
2
votes
2answers
153 views

How does one permissibly access files on non-booted system's user's home folder?

I have a dual boot system with Mint 17.1 and Centos 6.6 I want to access a file in my CentOS user's home directory from Mint. (I cannot boot CentOS right now.) What is a clean/standard method for ...
2
votes
1answer
242 views

Adding a user to a group by default

I have a group that all users on the system share. The group name is common and it is to allow for a universal fileshare for everyone on the machine. How would I make it so that all new users are ...
2
votes
1answer
12k views

Changing user and group ID system wide (including file system attributes)?

(this question possibly related to Linux: simulating/masking user ownership upon mount of 'external' partitions? - Stack Overflow) I typically use Ubuntu (currently 11.04) as my desktop OS; let's say ...
1
vote
1answer
453 views

Who is user “unset” in aureport?

I couldn't find this elusive "unset" user in /etc/passwd and there is no mention of him in man aureport although she scored the most number of hits on my audit log: # aureport -u -i --summary --start ...
1
vote
1answer
211 views

backup user accounts without giving a home directory to them

I am reinstalling the older Ubuntu machines with the latest RHEL 6.0 in servers. I have /etc/passwd and /etc/group and /etc/shadow file backed up for the list of user accounts that I need to create ...
1
vote
2answers
608 views

I can not log into Ubuntu 12.04

by ignorance and error I renamed the user_name of the directory /home/, called frank_account (home/frank_account) to sixven(/home/sixven) (using gksudo nautilus). Restarting Ubuntu, I get 3 users: ...
1
vote
2answers
39 views

Backup server users creation

I have a RHEL server which acts as the web server for all the users (around 1000 users). Now, I have a backup script which backs up the data (all data inside /home folder) into an external HDD. This ...
1
vote
1answer
1k views

Single-user binary installation location?

I'd like to install a binary for only my user, because I don't have root, and therefore don't have access to /usr/bin. I've tried ~/bin, and it can't find the binary. I'm on Mac OS 10.6.7. Is there ...
1
vote
1answer
530 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
1k views

Allow non-root process to access all home directories without compromising security?

Any ideas how to allow one non-root process to access (read&write) all home directories without compromising security? Normal users should not have access to each other's home directories. All ...