Earlier in this chapter, when you tried to cd to root's login directory, you received the following message: Linux, like UNIX, is a multi-user system, and file permissions are one way the system protects against any type of damage.
Let's examine all this a bit closer. This makes sense when you realise that directories are files as well. The file is not stored "inside" a directory. Files are stored in data blocks scattered alll over the disk partition. The directory is a special file that contains access information about all of the files references "inside" the directory.
Suppose you have read access to a directory, but you do not have read access to the files in the directory. You can still read the directory, or more corectly, the status information for that file, as returned by the stat system call.
That is, you can see the file's name, permissions, size, access times, owner and group, and number of links because you have access to the directory. The file itself is stored elsewhere on the disk this spot is identified by the i-node number.
The "ls -i" command shows the i-node number for a file. Write permission in a directory allows you to change the contents of a directory. Because the name of the file is stored in the directory, and not in the file, write permission in a directory allows renaming or deletion of files and does not require write permission of the file.
To be specific, if someone has write permission to your home directory, they can rename or delete your.
The permissions of your. Someone can rename a file even if they can't read the contents of a file. Execute permission on a directory is sometimes called search permission. If you found a directory that gave you execute permission, but not read permission, you could use any file in that directory.
However, you must know the name. You cannot look inside the directory to find out the names of the files. Think of this type of directory as a black box. You can throw filenames at this directory, and sometimes you find a file, sometimes you don't.
The read, write and execute permissions are stored in three different places, called user ugroup g or world or other o.
When you list this file with "ls -l" you will see -r--r--r-- 1 grymoire admin 0 Feb 1 All files have an owner and group associated with them. These permissions are determined by 9 bits in the i-node information, and are represented by the characters "rwxrwxrwx.
If the permission is not true, a dash is used to indicate lack of privilege. If you wanted to have a data file that you could read or write, but don't want any one else to see, the permission would be "rw Some people belong to more than one group.
If the computer is only used by one person, then groups aren't that useful except for set group-id programs, but that comes later. Let's assume you have several people using a computer, and you want to allow people in a group to have access to a directory.
Let's also say they belong to the same group as you. Assume the file is in a group directory, with the group "admin", and you wanted to allow them to read and You can create a directory that has read, write and execute permission for the group.
But you want to prevent people outside of the group from reading or changing the file. The chmod command can do this. So how can you change it to "rw-rw"?I can't delete a certain folder in Windows 7. It's not a system folder. It was created by an app. I get an error message "You need permission to perform this action.
How to give file permission to a specific user in a Group? Ask Question. First set the ownership of the file to Bob to allow for read+write access and set the group ownership to the g1 group. chown user_name file chown user_name folder chown -R user_name folder #recursive share | improve this answer.
answered Oct 12 '13 at Rahul. Jul 06, · To do this one may Grant List to the group, access the Advanced view and highlight the List grant and Edit it, and finally within the detail edit view check "Create Files / Write Data".
Ownership and Permissions. As a regular user, or deleted. As a rule, you should only grant read and write permissions to those who truly need them. In the following example, you want to allow everyone to write to the file, so they can read it, write notes in it, and save it.
g+w — adds write access for the group. caninariojana.com ( sp2, Vista+) Change file and folder permissions - display or modify Access Control Lists (ACLs) for files and folders.
iCACLS resolves various issues that occur when using the . I have a folder /home/samantha/folder that I want to share with the user tom. He can read/write the folder.
How do I do that? chown wouldn't do it because I still want to be able to be the owner o.