Changes permissions for a file.

There are three types of users in linux:

  • current user
  • current users group
  • all other users

The ll command (or ls -a) gives 10 chars, some examples:

  • -rwxr-xr-x
  • drwxr—r—

First char:

    • means file
  • d meant directory

The next nine are in groups of three:

  • r means read access
  • w means write access
  • x means execute access
    • means it is switch off

The nine are bundled in the following order:

  • user (u)
  • group (g)
  • others (o)

You can do one of the following commands:

    • add permissions
    • remove permissions
  • = set permissions

Example 1 - set current user to have read, write and execute rights, group users to be able to read and other to have no access.

chmod u=rwx,g=r,o= filename

Example 2 - remove read, write and execution writes for the group users and other users.

chmod og-rwx filename

Example 3 - change folder and subfolders

chmod -R 755 folder_name

See Also