Simple Permissions in Linux

To assign simple permissions in Linux:

Before assigning permissions, we have to know the alphabets assigned
read      - r
write     - w
execute - x
owner   - u
group    - g
others    - o

For Example - Write permission:

• Login as a root user ( superuser ) 
• In terminal type "chmod u+w directoryname"                                                                                                  -where 'u' stands for owners and 'w' stands for write                                                                You can give required permissions by modifying the above command as required
• To remove a permission, instead of  '+' in the above command use '-'                                                               ie., "chmod u-w directoryname"