Permissions are the unix way of controlling access to resources such as files, directories and devices and may be specified for an owner, group, or all users.

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Uppercase S in permissions of a folder

What does the letter S mean below? The file in question is a folder.                                     ...
10
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7answers
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Problem to launch java at Debian: “error while loading shared libraries: libjli.so”

I'm trying to launch java: $ java -version java: error while loading shared libraries: libjli.so: cannot open shared object file: No such file or directory $ ldd ...
8
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3answers
5k views

External hard drive permissions - ext4

I have an external USB 3 disk drive (2TB capacity) that is most likely going to be moved from machine to machine. The disk has a GUID partition table and an ext4 partition. I am unable to write to the ...
7
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2answers
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Group member cannot write even with write permission

The logged in user is a member of a group that has a write permission on a folder. But when this user is trying to write something, "permission is denied". The log below summarizes the question: ...
6
votes
2answers
172 views

Folder with ONLY write permission is useless… right?

Having worked with Linux for years, and finding myself with some free time, I decided to revisit some basics. So I re-read the stuff about permissions (without checking source code), and its special ...
5
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3answers
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granting write permissions to a group to a folder

How can I grant write permission to 1 group ? I have 2 users (alex and ben). alex is member of group alex and of group consult. ben is member of group ben and of group consult. I want to grant read ...
2
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2answers
644 views

Is a -rw-rw-rw- file really inaccessible inside a drwxrwx— directory?

Say I have a directory with these permissions: drwxrwx--- Inside this directory, a file with these permissions: -rw-rw-rw- Is the file readable/writable by everyone or not ? If not, how secure ...
9
votes
1answer
8k views

Group within group file permissions

I tried finding this on here, but couldn't so sorry if it's a duplicate. Say I have 2 groups and a user: group1, group2, user1 with the following structure: group1 is a member of group 2, user1 is a ...
9
votes
1answer
6k views

Why does root get Permission denied when accessing FUSE directory?

I use a FUSE filesystem with no problems as my own user, but root can't access my FUSE mounts. Instead, any command gives Permission denied. How can I give root the permission to read these mounts? ...
7
votes
1answer
4k views

Symbolic link permissions

I have access to a remote Linux machine where everytime I create a symbolic link, it is created by default with the following permissions: lrwxrwxrwx If I try to change the permissions of the ...
6
votes
1answer
3k views

Evince fails to start because it cannot read .Xauthority

I'm logged in remotely over SSH with X forwarding to a machine running Ubuntu 10.04 (lucid). Most X11 applications (e.g. xterm, gnome-terminal) work fine. But Evince does not start. It seems unable to ...
5
votes
2answers
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ISO file readonly?

I have an ISO file and I mount it under /mnt/isofile. Then I copied this file to another folder. But the contents are read-only and belonged to root. I tried to use chmod and chown. But it prompts ...
5
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3answers
494 views

Unix users, groups, and permissions

I don't understand unix users, groups, permissions, etc. For example, things managed by the chmod, chgrp, usermod, groupadd, etc. commands. How do all these things work?
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3answers
2k views

Permissions issues for shared directory on a server

The setup is we have a VPS running Debian Squeeze, and I've set up a shared directory for us to share files. So far I've followed this guide: ...
3
votes
2answers
74 views

Permissions to change only directory content and not itself

We have a directory and want to protect that from remove and rename, but we need to be able to rename, remove and create contents. What we can do?
3
votes
2answers
13k views

Mount device with r/w access to specific user

How can I mount some device with read-write access to specific user?
3
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2answers
385 views

Permissions of webserver's root directory

I've had this issue on several setups, and I'm unsure of how to handle it. At first, all of /var is owned by root:root. Clearly I don't want the web directory to be owned by root, so I do chown ...
2
votes
4answers
367 views

USB 500GB external drive mounted with undetermined permissions, missing data

Note: This situation is evolving. Please see the output at the end of this question for the current situation. I'm using Linux Mint 14. Recently, I repartitioned one of my hard drives, and I backed ...
0
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2answers
334 views

setfacl access issues

I have a list of users (user1,user2,user3,superuser). user1, user2 and user3 belong to a usergroup called normalusers . Now, I need to issue the access control list command for the user superuser to ...
5
votes
2answers
7k views

Using setfacl to allow group members to write to any file in a directory

I'd like to use setfacl so that anyone in group 'app' can edit any file contained within /usr/local/users/app regardless of what the traditional UNIX permissions say. I have two users john and ben. I ...
5
votes
3answers
9k views

How to check which Apache group I can use for the web server to write?

I'm trying to make Wordpress work. I currently have this error message: Could not create directory. /var/www/html/wp-content/upgrade/theme_name when trying to upload a theme. This is the ...
3
votes
2answers
49 views

Back up and restore file permissions

Is there a way to back up and restore file ownership and permissions (the things that can be changed with chown and chmod)? You can do this in Windows using icacls. What about access control lists?
3
votes
2answers
270 views

How does the 'passwd' command gain root user permissions?

How does Linux know that it has to give euid 0 (uid of root) to only certain process like passwd, setuid, etc. If a process can gain root permissions, will it not lead to potential security breaches ...
3
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1answer
1k views

Can't rename a directory that I own

I have a directory with a big load of sub directories. I own all of them, and the permissions are all 777. pascal@azazel /box $ ls -al total 147872 drwxr-xr-x 293 root root 12288 aoû 22 19:44 ...
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 ...
2
votes
4answers
409 views

Strange file ownership with Ubuntu

Normally we know when we create one file in Linux, the file's owner and group will set with the creator. For example, I have one user, usera, after I execute usera@srv1:$touch 1.txt I will find the ...
2
votes
2answers
3k views

can't change file permission

Whenever I create or copy few shell files to usb storage device, then I am not able to make them executable. If I create test.sh, it's default file permission will be 644, but when I execute ...
2
votes
2answers
817 views

Mount permissions always blocked

How do I authorise my non-root user to manually mount/unmount ALL media on my desktop. I always get denied permission. Media refers to all mountable USB devices and other partitions on my HDD as ...
2
votes
1answer
678 views

pure-ftpd permission denied on external usb drive

I have a sheevaplug PC (Debian installed) that I'm trying to setup my personal FTP server with. So far I was able to set up auto mounting and installed pure-ftpd. I currently have autofs setup to ...
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vote
2answers
52 views

Broken system after chmod -R 644 /

I use debian jessie and I have done one of those bad mistakes and broke my system with a mistyped command and worse mistakes that follow in such situations. Trying to fix some permissions I ...
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vote
2answers
35 views

facl ignoring the “x” permission but only on files

When I use setfacl to manage on what permissions should the children files / directories have, for some reason the files have all the permissions except the execute ("x") one. ...
1
vote
2answers
1k views

newgrp and groups assigned via pam_group.so

For convenience reasons I tend to assign special group memberships like floppy, audio, plugdev, video etc. via /etc/security/group.conf (pam_group.so) mechanism instead of adding all users to this ...
0
votes
0answers
38 views

DD-WRT: /tmp exec permission

After making a simple hello world OpenWrt package I installed it to the /tmp folder on the dd-wrt device. The program shows up in ls /tmp but when I try to execute it, it shows me /tmp/helloworld: ...
0
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2answers
142 views

File permissions of file when tranferring from Windows to Unix

When I am uploading a file from windows PC to Unix ,the permissions of file are --wxr----t on unix machine , whereas umask is 0022 .I am not able to understand from where is the file getting ...
16
votes
3answers
5k views

How to “jail” a process without being root?

Were I root, I could simply create a dummy user/group, set file permissions accordingly and execute the process as that user. However I am not, so is there any way to achieve this without being root?
21
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6answers
46k views

File permission issues with shared folders under Virtual Box (Ubuntu Guest, Windows Host)

I am using Ubuntu on Virtual Box and I have a folder which is shared between the host (Windows) and the VM (Ubuntu). When I open any file in the share folder in Ubuntu, I can not change it as its ...
21
votes
4answers
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Is there a reason why 'owner' permissions exist? Aren't group permissions enough?

I think I rather understand how file permissions work in linux. However, I don't really understand why they are split into three levels and not into two. I'd like the following issues answered: Is ...
7
votes
2answers
792 views

How are file permissions calculated?

Using chmod I could set the permissions for a file, but if the parent ( .. ) directory had conflicting permissions, what would happen? And if I create a new file, using touch or something similiar, ...
20
votes
2answers
3k views

How do I make a file NOT modifiable?

While logged in, I can do the following: mkdir foo touch foo/bar chmod 400 foo/bar chmod 500 foo Then I can open vim (not as root), edit bar, force a write with w!, and the file is modified! How ...
10
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4answers
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Which is more widely used: chmod 777 or chmod a+rwx [closed]

Out of the two options to change permissions: chmod 777 file.txt chmod a+rwx file.txt I am writing a document to send out to our customers, detailing that they need to change the file permissions ...
10
votes
5answers
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“Symbolic link not allowed or link target not accessible” / Apache on CentOS 6

I've got a brand new CentOS 6 installation, which has a symlink in the document root to my development files: [root@localhost html]# ls -l total 4 -rwxrwxrwx. 1 root root 0 Sep 18 20:16 index.html ...
6
votes
5answers
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Making a directory protected from 'rm -rf'

I just lost some data in folder A which was inside folder B after doing rm -rf B. Before I could realize what have I done, it was all over. Now a lesson is learnt, I wish to make some of my folder ...
9
votes
5answers
3k views

Directory with +x permission, parents without it. When would this be useful?

Say I have a folder called folder in the following path: my_path = /a/b/c/d/e/folder and a file called file in that folder. Then, say I run this command to remove group permissions under /a/ > ...
9
votes
4answers
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VSFTPD, 553 Could not create file. - permissions?

I've set up VSFTPD on Amazon EC2, with the Amazon Linux AMI. I created a user and can now succesfully connect via ftp. However, if I try to upload something I get the error message "553 Could not ...
7
votes
3answers
7k views

bash: /dev/stderr: Permission denied

After upgrading to a new release version, my bash scripts start spitting errors: bash: /dev/stderr: Permission denied in previous versions Bash would internally recognize those file names (which is ...
6
votes
2answers
7k views

Make all files under a directory read-only without changing permissions?

First, some background: /dev/md1 is a RAID-0 array serving as primary file store. It is mounted to /var/smb. /dev/md2 is another RAID-0 array storing backup snapshots taken from /dev/md1. It is ...
5
votes
4answers
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How to restore default group/user ownership of all files under /var?

I accidentally changed /var owner/group to my username and then changed it back to root, but not all the /var folders' owners are root, so is there anyway to change back owner/group of files/folders ...
3
votes
2answers
1k views

setuid and setgid confusion

I'm trying to fully grasp the concept of setuid and setgid, and I'm not quite sure in what way permissions are actually elevated. Let me provide an example: Users userA (groups: userA groupA) userB ...
2
votes
1answer
3k views

How to mount USB stick on Debian Sid?

I've just installed Debian Sid on my computer but I cannot mount external USB drives as you can see in the image. Mounting failed Cannot mount "SENZATITOLO" Not authorized What should I ...
2
votes
1answer
1k views

How do I restore default owner of files in /var/ directory?

Accidentally in /var/ directory I ran chown root . -R;chgrp root . -R. Now services like mysql don't start. Is there a way to restore default owner and groups? If there is no way, what is the default ...