All about Unix groups and access control.

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6answers
682 views

How can I find out which users are in a group within Linux?

I've recently been creating new users and assigning them to certain groups. I was wondering if there is a command that shows all the users assigned to a certain group? I have tried using the 'groups' ...
1
vote
1answer
30 views

(vsftpd) uploaded file group

I'm creating an ftp server with vsftpd, and I've almost finished, the only thing remaining is when I upload a file (logged as an user U), the file belongs to a group which has the same name (so group ...
2
votes
1answer
77 views

Negative GID in /etc/passwd?

I got following entries in /etc/passwd and /etc/passwd- on one system: userfoo:x:501:-513::/home/userfoo:/bin/false There's no group 513 anywhere on the system. What's this "negative" gid or a gid ...
1
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1answer
26 views

Group Directory permission

you have been asked by couple of programmers to make ProjectA a group directory on a UNIX server which allows them to create files under that directory to facilitate collaborative work, but only the ...
3
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1answer
109 views

How to specify owner and permissions for an NFS mount?

I have an NFS mount in fstab: 10.0.12.10:/share1 /net/share1 nfs rw 0 0 which defaults to root as owner and group and 777 permissions. How do I specify another owner and different ...
2
votes
1answer
109 views

scp file as another group

I would like to scp a file, however my primary group does not match the permissions of the destination directory so I get a permission denied message when I try to scp. I have the correct group as a ...
2
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0answers
122 views

Give a user permission to one folder

I have set up my machine so that my group "sftponly" can access the users home folder. But right now, the users in the group don't have permission to other folders, but they have permission to see ...
3
votes
1answer
89 views

Why there is a group member field in both /etc/group and /etc/gshadow

I am learning more about Linux user and groups in depth and noticed fourth field in both /etc/gshadow/ and /etc/group are exactly same. Do they have any difference or is there any special reason why ...
4
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2answers
88 views

Can an AIX user that appears in etc/group but not etc/passwd still log into a server?

Looking at etc/group and etc/passwd files, I see accounts listed in various groups in the etc/group file that do not appear in the etc/passwd files. Can these accounts still log in to the AIX server?
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4answers
4k 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 ...
0
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1answer
125 views

user exists when trying to add user to systemd-journal group.

I have been wanting to read systemd-journal by running/using journalctl -b . Now if I run it as a user I get the following :- $ journalctl -b Hint: You are currently not seeing messages from other ...
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2answers
44 views

Can't change group permissions [closed]

I am currently having an issue which is preventing me from editing the group permissions for my '/media/rnetBackup/' directory. I have tried editing the permissions using nautilus and using chgrp -R ...
0
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1answer
43 views

Why can't I create directories under /root as a member of root? [duplicate]

I've done the following: sudo usermod -a -G root userA sudo su - root cd / chmod 775 root ls -aln -- drwxrwxr-x. 6 0 0 4096 Sep 13 22:04 root I can cd /root from my userA, but I can't make ...
8
votes
1answer
1k views

File owner must belong to file group?

I have a rather simplistic understanding of file permissions on *nix systems. I understand that there is a file owner and file group, but is there a hard and fast rule on whether the said file owner ...
1
vote
1answer
115 views

Read file permission denied despite sufficient permissions [duplicate]

I'm attempting to cat a file with 770 permissions as a user who is part of the group (but not the owner of the file). This should provide sufficient permissions to my understanding, yet I encounter a ...
10
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3answers
28k views

How do i extend a partition with a LVM and the contained physical volume and logical volume?

On my 240 GB SSD i had at first two partitions, one containing the Logical Volume with Linux Mint and the other had contained a NTFS partition to share with Windows. Now i removed the NTFS partition ...
1
vote
1answer
397 views

groupadd: group 'terminal' already exists in Linux

I have created a group called "terminal" using groupadd terminal and when I list out the groups using groups command it will not show the newly created group name in the output but if I add the same ...
2
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2answers
315 views

Why can't I create a file in a directory where I have group write access? [duplicate]

There's a situation I don't quite understand. I have this directory, where the group 'webadmin' has rwx rights : $ ls -la total 8 drwxrwxr-x 2 root webadmin 4096 Aug 27 12:17 . ⋮ ...
13
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1answer
7k views

In /etc/group what is the meaning of the second field?

A sample /etc/group file contains the following entries: root:*:0: adm:!:4:logcheck antoine:x:1000: The man pages I've read (Debian & OSX) says the second field is to store a group password. ...
62
votes
3answers
81k views

Make all new files in a directory accessible to a group

Suppose I have two users A and B and a group G and a folder foo, both users are members of G (using linux and ext3). If I save as user A a file under foo, the permissions are: -rw-r--r-- A A. ...
1
vote
1answer
64 views

directory permissions [closed]

I'm currently working on a PHP server explorer, and I have to determine if a directory is empty or not readable because of insufficient permission. My web application is running under the user ...
4
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3answers
5k views

How to add group to a user without removing other group in suse linux with usermod?

I have one user, which has one primary group & one secondary group, like: [ testuser Welcome ~ ]$ id uid=2000(testuser) gid=2000(testuser) groups=2000(testuser),27(sudo),2001(testgroup) ...
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2answers
525 views

Where & How is user group information stored in Ubuntu? [closed]

Two places possible: /etc/group and /etc/passwd. If I use command: adduser [username] [groupname], then the user would be added to the group, and the file /etc/group would then be updated. However, ...
1
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1answer
59 views

Unable to execute program without root privileges regardless of group or permissions

avrdude is a simple tool that allows downloading of a program to a target microcontroller. For completeness, the command I am trying to issue is: avrdude -p atmega328p -c usbtiny -P usb -v -U ...
0
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1answer
127 views

Configure ssh users under a group [closed]

I created a group called ssh_group and currently have nearly 20 users under AllowUsers in /etc/ssh/sshd_config. After I created the ssh_group, I modified the AllowGroups line like this AllowGroups ...
3
votes
1answer
30 views

give group permissions to specific device

I have a panning web camera I built, (future robot arm). The camera pans via a web interface (cgi scripts and JS interface) which access an arduino. To enable sending of commands via the interface, I ...
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2answers
86 views

How to prevent selected users from using “newgrp” with a password [closed]

I'd like to know how can I avoid add some users to a group? I need to avoid some users join to a group --I want to lock a group from some users, not all. Details lgroupmod -L dba ==> This ...
2
votes
1answer
159 views

Udev rule- change group

I would like to change group of /dev/nvidia0. I was write udev rule: KERNEL="nvidia[0-9]", GROUP="video", MODE="0666" But it does't change group, after reboot file is in rootgroup. How do this?
2
votes
3answers
4k 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 ...
3
votes
1answer
245 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 ...
0
votes
1answer
37 views

Directory Permission Order [duplicate]

In Linux, let us assume we have a directory with the following properties: drwx---r-x 29 user1 group1 4096 Jun 22 14:11 dir1 can I, as user2 having group group1, navigate into dir1? Since ...
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0answers
129 views

groupadd failure: “Cannot open audit interface”

I'm trying to add a group in a chrooted environment: root@my-host:/# /usr/sbin/groupadd -g 101 games Cannot open audit interface - aborting. I'm operating with root permissions. Additional info: ...
3
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1answer
343 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 ...
0
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1answer
59 views

What is FreeBSD equivalent of Linux /etc/gshadow?

FreeBSD version 9.0 I have here. It has /etc/passwd and /etc/group files as Linux does. I figured that Linux /etc/shadow corresponds to FreeBSD /etc/master.passwd. The open question is what FreeBSD ...
1
vote
1answer
130 views

How To Logout and Apply New Group Settings [duplicate]

Can someone please tell me how to logout and log back in again via the command line so that I can apply a new group's settings to a user. To put this in perspective, assume that I am currently logged ...
1
vote
1answer
129 views

List of group id actually used on Debian

How can I get a list of group id which are currently used for Debian OS. I know that e.g. 0-99 are reservered for Debian "intern" things, but I'm wondering which ID is used for which group inside this ...
1
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1answer
257 views

Linux Root group change chmod for root owned to 770

I'd like to have normal user account assigned to root group (which I've done already) and change mod of all files that are owned by root user to 770, If I understood it well in result of that every ...
5
votes
3answers
2k views

How to restrict a user to one folder and not allow them to move out his folder

I have ubuntu server on digitalocean and I want to give someone a folder for their domain on my server, my problem is, I don't want that user to see my folders or files or to be able to move out their ...
3
votes
2answers
158 views

How to update user/group settings of a running process?

Suppose I change some user settings like its initial login group or add it to a new group. I now can do su user and work with these new settings. But all the previously running processes will still ...
0
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0answers
226 views

How to Sync UNIX Passwords SAMBA4.x?

My current server is running Debian 8 jessie with Samba 4. Its purpose will be to host a simple file sharing server for around 100 people on Windows machines. I already have a collection of UNIX users ...
2
votes
2answers
375 views

Getting Group Names for List of Users

I have a text files with a list of users formatted like: name1 name2 name3 ... Calling the command groups gives the primary group name for that user. ex: bash$ groups name1 name1: ...
1
vote
2answers
60 views

Adding user to the group owning a folder doesn't give that user access

I have the following folders: drwx------ 4 ccote domain^users 4096 Apr 17 11:18 ccote drwxrwx--- 2 ccote ccote_jponchar_gnicolas 4096 Feb 20 10:58 ccote-jponchar-gnicolas ...
2
votes
1answer
679 views

NFS permission problem with secondary groups

I have a server running Debian 7 that exports an NFSv3 share, and a client running Centos 5 that accesses it. This works fine, except for one issue with permissions based on non-primary groups. When ...
0
votes
0answers
77 views

Force group permissions

I have a problem with my Ubuntu server. I want all files that are created in a directory to have rwx permissions for the group. I set the parent folder UID with the following command: chmod -R ...
1
vote
1answer
278 views

sort file based one colum and group by another column

I have a file of three columns: 1 A 0.5 2 B 0.7 3 A 10 4 C 4 5 B 4 I want to sort the file by increasing order of column 3 and group by column 2 1 A 0.5 3 A 10 ...
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2answers
88 views

For given directory, how to check which files has specific permission flag in the group part?

I have a directory and i want to list all files that has permissions for writing in their group part, no matter to which group they belong. Also, how it can be done for the whole filesystem?
0
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1answer
46 views

What are the differences between sudo and the use of groups?

I know these are tools used for improving security. But what I would like to know is what they are and how they work?
2
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1answer
1k views

Difference between adding sudo user with adduser or gpasswd

To add a new sudo user I believe I can call: # to create a new user sudo adduser newusername and to allow this user to use sudo I can do: sudo adduser newusername sudo or sudo gpasswd -a ...
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vote
2answers
197 views

How to show all registred users and their groups with one command?

I was writing a test on basic Unix commands etc, and there was a question show all registered users and their groups with one command. At the same time I can't use getent command.
3
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2answers
1k 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 ...