All about Unix groups and access control.

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2
votes
2answers
72 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 ...
2
votes
5answers
15k 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 ...
19
votes
3answers
850 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 ...
3
votes
1answer
357 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 ...
0
votes
2answers
69 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 ...
11
votes
4answers
737 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
votes
1answer
61 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 ...
3
votes
3answers
158 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 ...
1
vote
2answers
122 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: ...
0
votes
1answer
4k 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 ...
4
votes
3answers
9k 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 ...
1
vote
1answer
68 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
votes
1answer
1k 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
94 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 ...
1
vote
0answers
75 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 ...
3
votes
3answers
122 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?
0
votes
1answer
53 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 ...
-1
votes
1answer
38 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 . ...
4
votes
2answers
618 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.
2
votes
3answers
856 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 ...
2
votes
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?
1
vote
1answer
69 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 ...
6
votes
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
votes
1answer
178 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 ...
4
votes
1answer
4k 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?
2
votes
1answer
219 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 ...
1
vote
3answers
253 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 ...
7
votes
4answers
263 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
votes
3answers
500 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
votes
3answers
38k 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?
90
votes
6answers
28k 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 ...
-1
votes
2answers
61 views

Clarification on permissions with GID & UID in UNIX

If Test1 & Test2 are users, then Test1 : UID : 501, GID :501, groups=501,100 Test2 : UID : 502, GID :502, groups=502,100 What will be the correct option from below and explain how? Test1 ...
0
votes
2answers
2k views

Privileges for jenkins at apache's folder

I'm having issue similar to this: How to copy files as Jenkins "post build" action if i don't have privileges to destination directory I'm willing to move/copy/rsync files from jenkins ...
1
vote
0answers
228 views

postfix expand ldap group AND afterwards resolve alias

We have a postfix server which has the user config stored in a openldap directory. Recently we also implemented ldap groups which are expanded by postfix. This works fine, unless the group expands to ...
3
votes
1answer
85 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
2answers
184 views

/etc files on a different partition

My setup requires that some of my /etc files reside on a separate partition. For this purpose I've created a softlink: ls -li /etc/group 956 lrwxrwxrwx 1 root root 21 May 7 15:48 /etc/group -> ...
2
votes
2answers
54 views

Who should own files shared by a group and where should they go

I am configuring a Linux work station that will be used by a small number of users (20-30). These users will belong to a small set of groups (5-10) with each user belonging to at least one group and ...
3
votes
1answer
849 views

Can one directory be owned by two groups?

Can one directory be owned by two groups (RHEL 6.2)? I have created one directory: mkdir /opt/shared, then I created two groups: groupadd sales groupadd marketing I added manually to each of ...
1
vote
2answers
52 views

Store a file for all users within a group

If user A is member of group foo, is it then possible for A to share a file for all members within foo without root permissions? chown foo:foo file Is not permitted without privileges. A can say ...
12
votes
2answers
11k views

Getting new files to inherit group permissions on Linux

I am having a problem with permissions on a Linux server. I am used to BSD. When a directory is owned by a group the user who owns it isn't in such as www-data, files created in it will be owned by ...
4
votes
1answer
108 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 ...
5
votes
1answer
1k 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 ...
1
vote
2answers
112 views

Command to know privileges of a user group

If I run cat /etc/group command or groups username I am able to know the list of groups as group of a particular user. Is there any command through which I could know which type of privileges a ...
6
votes
1answer
1k views

Why cannot a user change group ownership of his own files? [duplicate]

Why cannot a user change the group permissions of files which he owns. Let's suppose I have user martin: $ ls -lAd /home/martin/ drwx------ 8 martin martin 4096 Apr 20 01:06 /home/martin/ For some ...
1
vote
1answer
134 views

Re-add accidently deleted system group

In my attempt to delete the admin user group I accidentally deleted the adm system group. I "added it back" by issuing addgroup --system adm. I have a feeling this is going to bite me back later. Is ...
11
votes
2answers
828 views

Why is root in wheel and operator? Can root being in a group ever make a difference?

I just noticed on my FreeBSD machine that root is in wheel and operator. I'm trying to think of a situation where UID 0 being in a group would have any effect on... well... anything, and I'm coming up ...
0
votes
1answer
47 views

Trying to change GID on AIX server

I am trying to change GID on Unix server "AIX". I want to change mygroupname:!:79002: from group GID from 79002 to 79003. I have permission to use sudo /usr/bin/chgroup. I have tried everything, ...
4
votes
2answers
168 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 ...
0
votes
1answer
406 views

How can I allow a group to execute a command as another user?

I'm conservative about my sudoers policy. I'm trying to allow wheel users to run psql postgres postgres as the postgres user (because when ident that's the only way it works). root ALL=(ALL) ALL ...
5
votes
2answers
825 views

Group memberships and setuid/setgid processes

Processes which de-escalate privileges via setuid() and setgid() do not seem to inherit the group memberships of the uid/gid they set. I have a server process that must be executed as root in order ...