Table of contents
FileSystem Permission
ls -ltr
Permission Group Owner
From the above image, the red block indicates the permissions Yellow block indicates the Group and the Green block indicates the Owner.
How to check if it's a Directory or File?
In the Permission block, the first character defines it's a file or directory
'd'-for directory
'-' for files
Permission Description
Owner(u):- Permission used for the owner of file
Group(g):- Permission used for the member of group
Other(o):- Permission used by all other users
Permission | Access to a file | Access to a Directory |
Read (r) | display file contents and copy the file | View the contents of the directory |
write (w) | modify file contents | modify contents of a directory. |
Execute (x) | execute the file if it is executable. | Allow use of the cd command to access the directory |
Number | Permission Type | 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 |
From the above image, the permission is "-rwxr-xr-x"
-rwx--------->Owner has read, write and execute permission 4+2+1=7
r-x----------->Group has read and execute permission 4+1=5
r-x----------->Other has read and execute permission 4+1=5
If we want to change the permission for the directory and give only read and write permission.
Syntax:
chmod permission <filename/directory name>
chmod 666 node.ppk
chown- It is used to change the ownership permission of a file or directory.
chgrp- It is used to change the group permission of a file or directory.
Read about ACL and try out the commands
getfaclandsetfaclSo basically ACL stands for Access Control List its advanced permission mechanism of the filesystem. It allows you to permit any user group to any resources.
If we want to give specific permission to a particular user which is not a member of the group we still want to give the read and write permissions here ACL comes into the picture.
First, we need to install the ACL
Command-sudo apt install -y acl
sudo apt install -y aclTo set ACLs on a file or directory, you can use the
setfaclcommand.getfacl refers to get the file control access list.
