All about Unix groups and access control.

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1answer
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Creating users with groups in Ubuntu Server? [closed]

Typically when I create a new user in CentOS / Redhat with the command: useradd user The permissions that it is assigned to the user typically works fine. I believe everything is restricted to its ...
17
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2answers
40k views

How can I change a user's default group in Linux?

Being new to Linux administration, I'm a little confused about the following commands: useradd usermod groupadd groupmod I've just finished reading the user administration book in the Linux/Unix ...
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2answers
29 views

Automatically set group and permissions on files in a folder? [duplicate]

When I create new files and folders in a specific folder, I would like them to inherit the group and permissions of the parent folder. Is this possible ? For example mkdir -p example.com/public cd ...
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3answers
1k views

CentOS can't remove user from group

Asked and answered many times, but I can't get it working!!! (On CentOS) I have the user userA and I want to remove it from group sftponly. #groups userA userA : sftponly #id -Gn userA sftponly ...
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2answers
767 views

group option in fstab not working

I'm trying to take advantage of the "group" option for fstab entries and not having any success. From the mount man page: Normally, only the superuser can mount filesystems. However, when fstab ...
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1answer
55 views

Given a domain-controlled group, how can I get its domain?

I'm working on an application which collects data on groups. In my application I need to collect data and the residing users of local groups and send meta-data on domain-controlled groups. My ...
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2answers
41 views

Remove group ID from user

How can I remove a group (which was previously deleted) from a user which still references it? If I run groups, I get an error about a non-existent group: $ groups myuser dialout cdrom sudo dip ...
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1answer
42 views

What has priority - owner/user vs group permission? [duplicate]

I have just run into the case in which the owner-group of a file has more permissions than the owner-user of a file. user1@pc:/tmp$ ls testfile -l ----rw---- 1 user1 user1 9 Okt 16 13:16 testfile ...
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2answers
149 views

Precedence of user and group owner in file permissions

I just ran into something unexpected (for me) regarding file permissions on Linux (Arch Linux). Basically I have: userX in groupX fileX userX:groupX ---rwx---- What puzzles me: I cannot perform ...
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0answers
19 views

Configuring group access across a LAN

I have created a group called engineers on two VMs on the same 192.168.56.0/24 LAN. Is there any way the members from VM1 in engineers can view files created by engineers from VM2? I was thinking of ...
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1answer
26 views

Arrange for files created in a directory to belong to the directory's group

How do I set permissions so that whoever creates any files or directories in /directory, the group owner should automatically be the same group owner of /directory? This is on RHEL.
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1answer
63 views

can't execute a command even i'm in the group and command is -rwx--x---

I'm in $ORACLE_HOME/OPatch directory and when I type opatch then I get the response as, -bash: opatch: command not found If I do ./opatch, then I get the response as, /bin/sh: ./opatch: ...
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0answers
62 views

Tomcat unable to create file in dir owned by same group

I have a server running Tomcat, and I need Tomcat to create a file in a particular folder. Tomcat (technically a Java app) runs as the user 'tomcat', as evidenced by top: #top 1251 tomcat 20 0 ...
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5answers
98k views

How do I remove a user from a group?

Which command should I use to remove a user from a group in Debian? When adding a user to a group, it can be done with: usermod -a -G group user However, I could not find a similar command ...
1
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1answer
32 views

Find files belonging to a group

Actually I want to find all the files and folders that are under the same group, for example I have this : [test] user1/sam a.txt user9/sam b.txt user4/sam I'm looking for a command ...
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1answer
46 views

Debian: chgrp doesn't works properly on home folder

I'm trying to use chgrp on a folder named "share" in a home folder of the user "2". The ls -l presents the folder like this: drwxr-xr-x 2 2 bin 4096 Sep 29 13:09 share When using chgrp with the ...
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2answers
201 views

Reasons behind the default groups and users on Linux

Having a look at the default users & groups management on some usual Linux distributions (respectively ArchLinux and Debian), I'm wondering two things about it and about the consequences of ...
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2answers
56 views

How does bash pass user groups to a child?

It is well-known that if I add myself to a new group, that change will not be reflected until I log out and back in: $ sudo adduser me newgroup $ groups me sudo $ groups me me sudo newgroup $ This ...
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5answers
11k 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 ...
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3answers
345 views

Typical use case for a group password

I checked more than half a century worth Unix experience and neither my colleagues, nor myself has ever set a password on a group (sg and gpasswd). What would be a typical use case for a group ...
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1answer
157 views

Why does every user have his own group?

One thing I've noticed in a lot of recent distros is that users all have their own groups with the same name as their user name. What's the purpose of that? Groups are made to group users together in ...
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2answers
44 views

What is the significance of the “wheel” group? [duplicate]

I've commonly seen references to a wheel user group online as well as when setting up my sudoers file. Does naming a group wheel imply something special about the group or is it just a name for a ...
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4answers
658 views

Groups differ from the local ones when logging in remotely

We store our users in LDAP, alongside some groups that have meaning across different systems (organizational roles including wheel). There are also groups local to workstations, e.g. audio or video ...
3
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1answer
32 views

Why does uucp take group 10?

According to YoLinux, group ID 10 typically belongs to wheel. And on my Arch Linux installation, sure enough there in /etc/group is wheel:10. However, on my Ubuntu machine instead I'm greeted with ...
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3answers
126 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 ...
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2answers
62 views

Where is core group defined on coreos?

On CoreOS EC2 instance, I find the following: $ cat /etc/passwd root:x:0:0:root:/root:/bin/bash core:x:500:500:CoreOS Admin:/home/core:/bin/bash $ cat /etc/group wheel:x:10:root,core sudo:x:150: ...
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1answer
96 views

How to change primary group? [duplicate]

I have a user like this: uid=501(ironsand) gid=500(foo) groups=500(foo),10(wheel),497(git),501(ironsand) And to change primary group to ironsand like gid=501(ironsand), I typed this command: sudo ...
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3answers
7k views

What does GID mean?

What does GID actually mean? I have Googled it and this is what linux.about.com said: Group identification number for the process. Valid group numbers are given in /etc/group, and in the ...
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1answer
58 views

Groups in the Samba configuration

I can't quite understand groups. For example, lets say if I add the following into my samba config: valid users = @users Must the group users exist on my system or is a samba group itself? And if ...
2
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1answer
533 views

id command doesn't show all user's groups [duplicate]

I did a usermod to add the current user user in a group, but when I run id -Gn it only shows the main user's group: [user@computer ~]$ id -Gn user But when I specify the user, it works normally: ...
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1answer
268 views

how to make logstash read kannel log

I got logstash installed on ubuntu 12.04 using the apt repository. But logstash is not reading any document. In logstash log there are teh following: ...
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2answers
64 views

how to determine the permissions of groups?

When you invoke sudo, it prompts for password and then checks the /etc/sudoers configuration file to see if the user is permitted access to run the command. /etc/sudoers is the sudo configuration ...
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0answers
59 views

Which command would you use if you want to remove the password assigned to a group

Suppose I have one or more groups (as in the user database as backed by /etc/group or LDAP or NIS+...) configured with a password (for the sg or newgrp commands). Which command would you use to ...
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3answers
87 views

Is it possible to have a bashrc for a usergroup?

Is it possible to execute some bashrc file for all users in a group? If you can do that system-wide in /etc/profile then why not for a usergroup?
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1answer
28 views

As what user does a command end up executing? [duplicate]

How can I find out as what user a command executes? (I'm running Ubuntu, but I suspect the answer applies to Unix in general). What I'm trying to do is get msmtp running and logging to ...
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1answer
34 views

add groups from external file

I want to write a script which add groups to the system, specified in groups.txt file. content of groups.txt : group01 : computer group02 : electronics group03 : IT . ...
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1answer
287 views

groupadd failure while writing changes to /etc/group

I have been following this guide on installing debian-kit on my Sony Xperia Tablet Z and the installation goes fine until I try to apt-get install andromize which fails with the error groupadd: ...
3
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2answers
180 views

Short, simple command to create a group if it doesn't already exist?

What is the cleanest way to modify this command in bash to only run if the group does not exist? groupadd somegroupname A one-liner would be best.
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3answers
229 views

adding list of users to multiple groups

I have a shell script which add list of users which is listed in another file lets say users.txt. After that, I want my script to add users to multiple existing groups with condition, one user may ...
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3answers
1k views

Limited SSH user on Ubuntu 12

I'm running Minecraft on a server. How can I give my friend SSH access just to the minecraft folder (a root folder), the screen command, and some ports?
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1answer
52 views

Troubleshooting joining a group in Mint in VirtualBox [duplicate]

I am trying to join my user to the vboxsf group to access a VirtualBox shared folder from inside my Linux Mint virtual machine. However I'm encountering a problem that I can't troubleshoot. I've ...
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2answers
6k 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 ...
0
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1answer
81 views

Cannot lock group file: already locked

I'm trying to add a group using this command: groupadd somegroup which returns: Cannot lock group file: already locked. I did some research and most of the solutions require removing a lock file ...
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1answer
962 views

View List of Sudoers with No Sudo Priviledges

If I'm not a sudoer, is it possible to view the list sudoers? Does /etc/group show this information?
1
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1answer
157 views

AT&T UNIX System V Release 4 - How do I create a new “Administrator” user?

I am running AT&T UNIX System V Release 4 Version 2.1 inside VirtualBox, and want to create a new "user account" for myself. At first, I simply created a new user with the useradd command, but ...
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3answers
174 views

Delete non-unique group with group ID as primary group of a user

So say I have two groups with names testing1 and testing2. Both groups have the same group ID of 2000. Then I add a user named testing-user with GID of 2000. Along the way I want to delete group ...
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4answers
210 views

Groupwise uniq command?

I am searching for a command to get from a file in this format: hello 32 hello 67 hi 2 ho 1212 ho 1390 ho 3000 To this format (deduplicate by taking the last row of a "group"): hello ...
2
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3answers
357 views

User permissions problem Linux

Every time I create a new file from "eclipse", I need to run these two lines of code to get the r/w permission: chmod -R 775 /var/www/folder/filename.extension And/Or sudo chown -R ...
12
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3answers
32k views

Change gid of a specific group

I'd like to change group id of a specific group. There are so may solution for changing the gid of a file or directories. But that's not what I want. Is there a way to do that?
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6answers
24k views

Where did the “wheel” group get its name?

The wheel group on *nix computers typically refers to the group with some sort of root-like access. I've heard that on some *nixes it's the group of users with the right to run su, but on Linux that ...