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

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4
votes
2answers
112 views

Is it a good practice to have different users for different contexts?

I'm a software developer and I have a new laptop with Ubuntu. I plan to set up this laptop as a development workstation where I'll do my professional work (for my company) and also I'll develop some ...
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 ...
4
votes
1answer
6k views

Expired password and SSH key based login with UsePAM yes

There is a SLES 11 machine. The users logs in via SSH and pubkey (mixed, some user uses password, some use ssh key) The sshd_config has: UsePAM yes PasswordAuthentication yes PubkeyAuthentication ...
4
votes
1answer
1k views

Restricted ssh remote execution with arguments

I need to enable remote execution of a shell script on a server, but deny all other access. The script is a toggle that accepts a single parameter (on/off/status). This comes close to answering my ...
4
votes
2answers
1k views

talkd doesn't print a message

I wanted to use talk with my brother (we both have Debian jessie). So i installed inetutils-inetd, inetutils-talk, and inetutils-talkd. Now i wanted to try wether it works. So i created a testuser ...
4
votes
2answers
493 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
1answer
197 views

Easiest way to manage users for two machines

I'm administrating two ubuntu desktops and one debian server. There are abount ~20 active users on the desktops. A few (5-10) user accounts are added each year and about the same amount become ...
4
votes
1answer
306 views

Can linux use a mix of SHA-1 and CRYPT passwords?

We have an automated sync-routine that uses useradd to create new users on a Ubuntu 10.04 machine. The application launching the routine provided both username and CRYPT-encrypted password. However, ...
4
votes
1answer
2k views

How can a user run a program in kernel mode?

Is it possible for a user to run their own program in kernel mode? How could a user accomplish this? What weakness in the system's protection mechanism would they have to bypass? I'm thinking that a ...
4
votes
4answers
13k 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 ...
4
votes
1answer
622 views

Force pubkey-auth user to set password at first login

When I create a new user account I ask users to send me a public key, and want to force users to set the password the first time they log in with keypair authentication. If I create an account with an ...
4
votes
2answers
4k views

SSH not landing in the home directory

I have recently installed Raspbian into a Raspberry Pi. As part of the installation process I changed the user name and group from the default (pi) to my own (let's call it user) using usermod and ...
4
votes
2answers
5k views

'mysql' user and group creation, ownership settings

I know what the linux command chown does, I used it to change the ownership or group of a file. If there is a MySQL installation on a Ubuntu machine, I saw some people doing the following thing: ...
4
votes
1answer
220 views

How do you give a developer group access to apache, MySQL, php and the webroot?

We have 3 web designers that are currently logging in to our server via root to configure apache and setup websites. I have very basic linux knowledge (I'm a web designer) and have created users and ...
4
votes
1answer
185 views

Where are passwords stored and how are they encrypted in OS X?

I know that on a Linux system passwords are stored in /etc/shadow and are salted and encrypted using a one way hashing algorithm like MD5, SHA-256 or SHA-512. It looks like there is no /etc/shadow ...
4
votes
2answers
1k views

recommended procedure to create a user/group during RPM install

after trying hard to search for RPM best practices guides and finding virtually none, to my surprise, I resort to the community - I need to ensure that some users and groups exist after the ...
4
votes
3answers
1k views

Permanently switching to zsh in a script, without being root and without being asked for the password

Is there any way to run chsh -s /bin/zsh without being root and without being asked for the password? I want to put it into a non-interactive script that isn't called by root.
3
votes
1answer
216 views

Enable superuser when logged in with another user

Suppose that the machine has two users: Alice (admin) Bob (standard user) While Bob is logged in, how can Alice modify a root file (Bob does not have this permission even with sudo)? Alice tried: ...
3
votes
2answers
8k views

change root account username

In windows it is possible to change administrator username for security reasons. Is it possible to change root username in Linux too?
3
votes
6answers
4k views

sort ls output by users

On Linux, is there a way to sort ls output by users? What I try to achieve is something like this: user_a   file1 user_a   file2 user_b   another_file user_c   this_file user_c ...
3
votes
5answers
27k views

What is the command for listing all users who are members of the admin group?

I am looking for the name of the superusers list on Fedora. (On Ubuntu is seems to be "sudo".) I want to add one of the users to the superusers list. The groups command only lists the groups of the ...
3
votes
3answers
2k views

Killing other user processes

There are certain user environments in which we have to login during certain performance testing and and kill all the process running in that environment. The environment names are like rswrk01, … up ...
3
votes
3answers
385 views

Why only one active group at a time?

As far as I understand the users in Unix system can belong to multiple groups and one of them will become the primary group for that user. Others will be supplementary groups. All of this User/Group ...
3
votes
4answers
23k views

New user with root access in Linux Debian

I've created a new user by using "User Accounts" in "System Settings". How do I grant rights so that this new user can have the same level of access as root?
3
votes
4answers
6k views

Allow paswordless user to change to another passwordless user

I have two users dev and tomcat neither of them have a password. How can I allow dev 1 do su - tomcat without having him having to enter any credentials? 1 connects with ssh keyfile
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
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 ...
3
votes
3answers
462 views

How to switch back and forth between users quickly on a single terminal?

I'd like to switch to another user without logging out the first user, then log in as a third user without logging out the other two, and so on, then switch between all users quickly. I'd like to ...
3
votes
1answer
4k views

What steps to add a user to a system without using useradd/adduser?

I was browsing through some Linux questions and saw this interesting question. What steps to add a user to a system without using useradd/adduser? The one possible way that comes to my mind is, ...
3
votes
1answer
95 views

Does root not require a password to log in as a user?

Does root not require a password to log in as a user even though a password has been set for that user? When I am logged in as "root", su user logs me in as "user". There is no prompt for a password. ...
3
votes
2answers
12k views

su - user doesn't work for users without a password

I've created a user on CentOS with useradd -M username. Now, I want to become that user just like su - username. It asks me for a password for that user but I didn't set a password for that user. As ...
3
votes
3answers
9k views

Setting default username and group for files in directory

Using this helpful post I am able to set a default group and file permissions in a folder. I'm having trouble setting a default owner (teamlead uid 1234). setfacl -d -m g::rwx /my/test/folder ...
3
votes
2answers
218 views

Unix command to find files read by specific user

I would like to find files accessed by specific user (even just read) within a folder tree. I thought the find command had this option, but it actually just searches for owner user. Is there any other ...
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 ...
3
votes
2answers
3k views

Change file ownership, based on previous owner

I am a moderately new linux user. I changed my PC, and started using CentOS 7 from CentOS 6. So I attached my previous hard disk to my new pc to take backup of my files. Now, copying the files (and ...
3
votes
3answers
40k views

How do I know a specified user's permissions on Linux with root access?

I have root access to my local server. And some days ago my colleague created a user on that server, giving me the uesrname and password. But the user has a minimized permissions. Like the user can't ...
3
votes
2answers
8k views

How can I have a separate umask for directory or user?

I want a separate umask for a directory or a user. How can I do this? Edit: I am using Debian 6. The reason why I want to do this is, I want all my SFTP users to create files with write on group. ...
3
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 ...
3
votes
3answers
4k 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 ...
3
votes
2answers
936 views

Preserve ownership with rsync and nonexistent user

I have two computers with the same user, me@Home and me@Work. I usually kept their folders synced by bringing Work home (it's a laptop) and rsyncing over LAN. However, now I'm not bringing Work home ...
3
votes
1answer
237 views

Default files in home dir for each user

I'm using ubuntu server 14.04. I want to add some files and folders by default in each user's home directory, whenever a user account is created.
3
votes
1answer
257 views

Two users with different permissions on same directory

Is it possible to give two users different permissions on the same directory? I want to use it for ftp: userFull gets R+W and userLim gets only Read, depending on who logs on. Im getting stuck on the ...
3
votes
1answer
348 views

Is running programs as another user useful?

After watching a talk by Douglas Crockford on security where he talks about how browsers got the right answer to the question "Who's interest does the program represent?", I wondered if it was ...
3
votes
1answer
1k views

Is there a way to find out how many instances of the root user are logged into a Linux machine?

We have a handful of users that login to our Linux virtual machine as root either through the vSphere client or through SSH and I want to see if there is a way to tell if multiple root users are ...
3
votes
1answer
4k views

Difference between passwd and passwd- file [duplicate]

Possible Duplicate: Who creates /etc/{group,gshadow,passwd,shadow}-? I have a strange passwd- file in /etc, notice the trailing dash: root@ubuntu:~# ls /etc/passw* /etc/passwd ...
3
votes
2answers
273 views

Execute command on shared account login

At work our team uses a shared account "appadmin" to administer our application. At login, each one of us sources an "aliasrc" file containing his or her preferences. (aliases, display, prompt, ...). ...
3
votes
1answer
282 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?
3
votes
3answers
101 views

Understanding a couple of points regarding root privileges

I just wanted to confirm my understanding of a couple of things related to root privileges. Is it correct that: The user name "administrator" is not a reserved name with implied privileges, it is ...
3
votes
1answer
6k views

Home Directories and pam.d using LDAP

Background: I'm not too familiar with the ins and outs of pam and LDAP authentication on a configuration side. I've used systems that use pam but I've only worked on applications, not systems ...
3
votes
1answer
196 views

Gives access to root user for a period of time

I want to know if it's possible to give access to root user for one week or a month, for example. It's possible to increase the period of time before the defined period ends? Is it possible to give ...