How to Change Permissions in Symbolic Mode

1. If you are not the owner of the file or directory, become superuser.

   Only the current owner or superuser can use the chmod command to change file permissions on a file or directory.

2. Change permissions in symbolic mode by using the chmod command.

   $ chmod who operator permission filename

   who operator permission	who specifies whose permissions are changed, operator specifies the operation to perform, and permission specifies what permissions are changed. See Table 51-6 for the list of valid symbols.
   filename	Is the file or directory.

3. Verify the permissions of the file have changed.

   $ ls -l filename

Examples--Changing Permissions in Symbolic Mode

The following example takes away read permission from others.

$ chmod o-r filea

The following example adds read and execute permissions for user, group, and others.

$ chmod a+rx fileb

The following example assigns read, write, and execute permissions to group.

$ chmod g=rwx filec