managing file ownership and permissions for linux

owner-permission

ownershop
  --    chmod / chgrp

permission
  --  files & folder
  --  chmod
  --  octal
  --  umask

special permissons
  - SUID, GUID, stick bit
  
  
  sudo chown [user]:[group] [filename]
  sudo chgrp [grp]  [filename]


ls -l

-rwxrwxr-x  1 root kia      9664 Jun 14 08:40 a.out


here first - indicate file type -- i.e file / folder or link

- for file
l for link 
d for directory

after first character there are nine characters which specifies the permissions of the file

rwxrwxr-x  
r   -- read
w   -- write
x   -- execute


first 3 character specifies owner of the file  i.e permissions for the owner of the file

second 3 characters specifies group of the file i.e permissons for the group of the file

last 3 characters specifies the permissions for the everybody else has


type  | User  | group | other |   octal
  d   |   7   |   5   |   5   |   r = 4
  d   | r w x | r - x | r - w |   w = 2
  -   |   6   |   6   |   4   |   x = 1
  -   | r - x | r - x | r - - |