All about Unix groups and access control.

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1answer
18 views

Does LDAP take care of all users and groups on a system?

I have been following the tutorial here to try out LDAP. I know that a Linux system has groups like mysql, sudo, video, dial-out etc. Do I need to add these to my directory? Are these served via LDAP ...
5
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0answers
32 views

systemd user cannot get user group's ability

I added a non-root user in docker group, and an other service run as this non-root user connect to docker daemon. but the service can not work. I do a test example for this : root@# systemctl start ...
5
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1answer
815 views

Implications creating System Accounts “useradd -r” Linux Fedora/RHEL/CentOS

I want to know what are the implications of create an account using -r option? # useradd -r ... The help says: -r, --system Create a system account. System users will be created with no aging ...
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0answers
27 views

access denied for folder in NFS share possibly for new users only. Why? [on hold]

On a one of our NFS filers, a user is unable to access the folders having group ownership and permissions. $ id -a uid=3234243(user1) gid=18027(sv_users) groups=18027(sv_users),18606(lts) $ls -ld /...
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0answers
29 views

Cannot add group on RHEL desktop

Question: why does the groupadd fail here? Is it related to SELinux or maybe a bug? I found the mv /etc/group+ /etc/group problem via strace groupadd.. [root@notebook ~]# groupadd testing groupadd:...
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2answers
94k 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
3k views

Can't access Apache log folder

I want to see apache log file. This is what I tried: I granted most all permissions to apache2 folder. hieund@hieund:/var/log$ sudo chmod a+rw apache2/* But I can't cd to it. So I add my user to ...
0
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1answer
31 views

How do I add a user to a group

How do I add a user to a group. This is on a system with no root password and only a single user pi with sudo privileges. usermod seems to have been designed to make this as difficult as possible.
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0answers
20 views

How to prevent special group to delete files or folders?

Folder path: /var/www/html group name: "ftpusers" user: "admini" How to prevent from group "ftpusers" to delete files or folders in html folder, but allow them to create files or folders? User "...
0
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1answer
29 views

Unix winbind groupmap

i got Linux server (SLES 12) joined in Windows AD with winbind and samba services. I got unix group "mqm" and windows AD group "67uts-mq-admins". I want to map windows AD to unix group with "net ...
0
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1answer
35 views

Centos, uploaded files from application have different owner and group [duplicate]

I have an application that uploads a file via SFTP using sftpuser. Once the file is uploaded the owner and group is user1:user1. The owner of the parent directory is apache:apache. I can not figure ...
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0answers
13 views

What will be the result when USERGROUPS_ENAB is set to no in /etc/login.defs and no groupname is specified when using the commnd useradd

The default command when we add a user is: sudo adduser -m -g initial_group -G additional_group -s login_shell user_name In /etc/login.defs USERGROUPS_ENAB is set to yes by default This means ...
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0answers
35 views

Does changing your OS (fedora>OpenSuse) or FS (ext4>btrfs) “break” rsync?

I am using a rather simple script to do incremental backups of my laptop to my external HDD's, where the core line is probably the following: rsync -arbuv --delete --progress -exclude-from=/backup-...
2
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1answer
10k views

Trouble adding existing user to existing group in ubuntu

I was trying to add a user called bill to www group useradd -G www bill It gives me error UX: useradd: ERROR: bill is already in use. Choose another. I checked if this user already in the group ...
4
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1answer
786 views

In my secure log there is a new group added that I'm unsure about after adding semanage

I installed semanage onto my CentOS 6.2 box and I was going through my secure log after the install and noticed this entry: Aug 31 22:12:17 xxxx groupadd[12929]: group added to /etc/group: name=cgred,...
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2answers
361 views

Delete every users from a group

I search a clean way to delete every users from the 'sudo' group. On several distributions the user created during the installation process has sudo rights, I don't want this. I search for an ...
2
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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 ...
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3answers
19k 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 GID ...
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2answers
64 views

Files are created with old group ownership even though the creator doesn't belong to old group anymore

I am currently preparing for LPIC Level 1 exam and I have been practicing management of user accounts on CentOS 7 system installed on VirtualBox. Firstly, as root, I created a user 'foo' with group '...
7
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5answers
294 views

Changing Unix group for files

I have a file that a colleague and I are editing together, on a Unix system. We are using Unix group permissions to edit it. We have one Unix group that we are both members of. Whenever I save the ...
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1answer
49 views

Where does Linux track who is a group admin through the gpasswd command?

If I modify group membership and admins using the gpasswd command and add a user as a group admin Linux will allow that user to perform tasks otherwise reserved by root. Ex. [test1@centos ~]$ ...
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3answers
32k 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 ...
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2answers
94 views

Meaning of the colon and x in getent group

I'm new to Linux and I came across the command getent group sudo to list sudoers in sudo group and I got the output sudo:x:27:lion now I wounder what is the meaning of :x:, colon and 27 ... also I see ...
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1answer
226 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 ...
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1answer
3k views

Apache, Group Permissions and User Uploads

I have a folder named "digitalgoods" with the following ownership -- apache:apache residing outside of the htdocs folder and is therefore not accessible to the public. However I need the same folder ...
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2answers
68 views

Why do you have to be a member of a group to make that group the group owner of your file?

In unix, I know that you have to be a member of a group to change the group owner of a file to that group even if you own it, but can someone please tell me why. I don't understand why you shouldn't ...
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3answers
41 views

Is group priority available?

[tjm@ArchPad bin]$ LANG=en [tjm@ArchPad bin]$ pwd /usr/bin [tjm@ArchPad bin]$ ll | grep wireshark -rwxr-x--- 1 root wireshark 88K Apr 25 00:22 dumpcap -rwxr-xr-x 1 root wireshark 2.0M Apr 25 00:23 ...
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1answer
62 views

Cannot Bash chgrp GROUP /home/*/SOMEFILE/ How to do it?

So am setting a code that will change group owner of the file to a specific group. PS there are more than 10 users, with same folder and file structure, and i want change the ownership of a specific ...
1
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1answer
10 views

Significance of groups assigned to user by Debian installer (only)?

I want to remove my default user from the sudo group. IOW I want to change it to an unprivileged account. However it also seems to be a member of ten other system groups. What is the overall ...
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2answers
13k views

What is nobody user and group?

On my server (Synology DS212) some files and folders have nobody nobody users and groups. What are the characteristics of this user and group? Who can write of read this file? How can I change it ? ...
0
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1answer
67 views

usermod -a -G group user not work [duplicate]

I use Ubuntu 12.04. I am trying to add the user gefalko to the www-data group. I use root@xxx~# usermod -a -G www-data gefalko If I understand correctly, I should now see www-data in the output of ...
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4answers
977 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 ...
1
vote
1answer
34 views

Linux, having trouble adding user to second group

Redhat Linux 5.10 (Tikanga) I'm trying to add an existing user to a second group. The user is already part of the primary group called "prim" and the secondary group I want to add him to is "sec". I'...
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0answers
17 views

useradd failing [duplicate]

Debian 8, I'm trying to allow a user to run Wireshark. user1@system:~$ sudo useradd -G wireshark user11 useradd: user 'user11' already exists However: user11@system:~$ groups user11 cdrom floppy ...
3
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2answers
96 views

Primary and secondary groups

So I've got the basics of primary and secondary groups down, but still have some questions I can't seem to find solid answers to: Can many users belong to the same primary group? Can one user's ...
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3answers
85 views

Predefined group ids across Linux distros?

In order to successfully implement w/r access via ACL for external storage with ext4 fs I need to assign default group id for files on storage. LSB_5.0.0 say: This specification makes no attempt to ...
1
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5answers
58 views

Show a user exists command

Is there a command that shows a user exists and is assigned to a group? I have just used the command usermod -a -G [GROUP] [NAME OF USER] and assigned a user to a group but, I was wondering if there ...
1
vote
1answer
57 views

How to avoid that Geany editor changes owner of file when it's edited?

I use Geany to edit files in a web app that resides in /var/www. The owner and group of /var/www and all sub directories and files are www-data:www-data. My user account is a member of that group and ...
154
votes
8answers
245k 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 (...
0
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1answer
63 views

trouble understanding GID and chmod g+s

I am having trouble understanding the GID and the command chmod g+s I read this as setting the permissions of the passed file or directory, for the group, as +s (sticky im assuming?) Does the +s mean ...
4
votes
1answer
4k 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: [...
1
vote
2answers
64 views

How can I create a sub-directory where my group has no write permissions?

I am working in my Tomcat deployment directory. The files in the directory have the permission: drwxrwsr-x. 10 tomcat www 4.0K Mar 15 15:14 webapps A sample sub-directory within webapps looks ...
2
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4answers
348 views

Can a Linux user have multiple primary user groups?

How many primary groups can an individual Linux user have? If they can have more than one, how does one go about assigning multiple primary groups to a user? If it's just one, what's the cause?
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3answers
139 views

File System Permissions: User who can backup all files

I am setting up an automated backup job for some computers on my network. There is a server that will, daily, run an rsync command to backup each of the other computers. I'd like the user that the ...
0
votes
1answer
30 views

What is each group's permissions, and what is the “ranking” of each group (most privileged to least)?

My question is basically the title, but for further clarification with the ranking part, I'm asking about who inherits permissions from who, along with any additional permissions for the group as well?...
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0answers
50 views

How to set correct user group rights to application running with java?

How to set correct user group rights to application using java? There is this scenario: 1) I have created user group and user (the same) - call it "groupgroup" 2) When I create a file with this ...
3
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2answers
63 views

Why are privs required to setgid() to supplementary groups

The various set*gid() system calls require privileges to change groups except in a very few cases. Changing primary group to one of the processes' supplementary groups does not appear to be one of ...
24
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3answers
19k 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 ...
0
votes
1answer
74 views

Access from multiple users to same directory but can't change directory group to a common one

I need to give full access to user1 and user2 to this directory: drwxr-xr-- 3 oracle dba 4096 feb 9 23:16 scripts I can't change directoy group because probably that group is needed for other ...
118
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6answers
42k 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 ...