Question

1. the commands you used to create the directories and files in Linux and Windows;

2. the commands you used to determine default permissions in Linux and Windows;

3. the commands you used to change permissions on your files in Linux and Windows;

4. a paragraph about how directories and file permissions work and what was the same or different between Windows and Linux.

Answer 1

1.

create directory command both in windows and linux mkdir <directory_name>
create file command in  linux touch <file.txt>
create file command in windows is echo This is a simple test text file > simple.txt
This creates a file named simple.txt

2.

The command in unix is umask. In my system it gives
$ umask
0022
It is represented in octal value , First 0 indicates it is octal. Hence the value is actually 022

The list of Octal umask permission values are as below
Octal value : Permission
0 : read, write and execute
1 : read and write
2 : read and execute
3 : read only
4 : write and execute
5 : write only
6 : execute only
7 : no permissions

considering above table of permission value the umask
Bit who File permission
0 Owner read, write and execute
7 Group No permissions
7 Others No permissions
So when my umask returns 022 it indicates
owner can read,write and execute the file
users of the same group can read and execute the file
Others can read and execute the file .
So by umask 022, the user can write data, but anyone can read data.

In windows it is
c:/>windows whoami /priv

3.

In linux
chmod options <filename>  
options can have following values

Number Permission Symbol
------------------------------
0 No Permission ---
1 Execute --x
2 Write -w-
3 Execute + Write -wx
4 Read r--
5 Read + Execute r-x
6 Read +Write rw-
7 Read + write + execute rwx

$ chmod 774 myfile.txt
Here the digits 7, 7, and 4 represent the permissions for the user, group, and others.

In linux apply following command

$ ls -l a.txt
-rw-r--r-- 1 apple staff 0 Feb 28 18:33 a.txt

In windows NTFS, the file/folder permission can be set from the properties context window of the file/folder as below

4.

Meaning of file/folder permissions

See the command
$ ls -l a.txt
-rw-r--r-- 1 apple staff 0 Feb 28 18:33 a.txt

The first column of the above list shows the detail of file permission. The first character '-' indicates it is a file. For directory it starts with 'd' for example as below

drwxr-xr-x 2 apple staff 64 Feb 28 18:53 test

r - It stands for Read permission. Whether the file may be read. If it is a directory, this permission allows to list the contents of the directory.

w - It stands for Write permission. With ths permission, a file may be written to or modified. For a directory, it indicates whether you can make change the content of directory like delete, rename or create a file/folder.

x - It stands for Execute permission. Whether the file may be executed. For a directory, this attribute decides whether an user has the permission to enter, run a search through that directory or execute programs from this directory.

The Linux file system is derived from Unix, which is much older than Windows. Hence the implementation of file permission in linux and windows are different, though conceptually they handle the same set of file management scenarios.

Each file could have three sets of permissions – access permissions for everyone, access permissions for its 'owning group', and access permission for its owning user. These three permissions are either Read, Write, or Execute.

When a new user is created, who needs write access to the file, if a new user joins in some other department and , he is not in the owning group of the file, it is needed to create a new group that comprises both this new user and the previous department, and replace the 'Owning Group' with the new group. For larger organizations, these permissions become messey as new user joins.

However, the Windows file system, every file can have permissions assigned to it, for any number of users, any number of groups, or “Everyone”. There are even several different definitions of “Everyone” – authenticated users, network users, guests, system users and so on. At the folder level, these fine-grained permissions can be set even for inheritance by subfolders and their nested sub folders, so that any changes at the parent folder will be replicated to its child subfolders automatically.