How to Set-Change Permissions on Files and Directories By the Command Line on Ubuntu 14.04 Trusty LTS Linux

Setting Permissions on Ubuntu GNU/Linux

This tutorial will guide you step-by-step on How to Set or Change the File/Directory Permissions on Ubuntu 14.04 Trusty Tahr LTS Linux.

To Follow the Tutorial you will Need to have a Little Practice to Work on the Ubuntu Linux Console Terminal Command Line.

Included in the Article Links to Guides on Getting-Started with Command Line on Ubuntu Linux and to Setting Ownership over Ubuntu File System.

1. Open Shell session
   Ctrl+Alt+t on Desktop
   (Press “Enter” to Execute Commands)

   

How to Quick Start with Command Line on Ubuntu

Console Quick Start Guide
Getting-Started with Terminal on Ubuntu

2. Who Can Change File’s Permissions?.

   • You Can Freely Change Permissions over Files/Directories Your User’s Hold.
   • But you need Admin Super User Powers to Change Permissions on Entities he Do Not Hold!

3. Setting Up Permissions on Files and Directories.

   Basic Building Blocks for the Permission Command.

   Ownership Types:

   • Use ‘u‘ to Setup Permissions for the User Owner
   • Use ‘g‘ to Setup Permissions for the Group Owner
   • Use ‘u+g‘ to Setup Permissions for the User and Group Owner
   • Use ‘a‘ to Setup Permissions for All (World)
   • Use ‘o‘ for Revoking Actual Permissions and Giving Permissions to the Others (the Before Disabled ones)

   Permission Types:

   • Use ‘x‘ to Setup Execution Permission
   • Use ‘w‘ to Setup Write/Delete Permission
   • Use ‘r‘ to Setup Read Permission

   Giving/Removing Permissions:

   • Use ‘+‘ to Give Permission
   • Use ‘–‘ to Remove Permission

   Generic Permission Command Form:

   chmod ownershipSubject[+/-]r/w/x [myEntity]

   For Instance :

   mkdir $HOME/world

   To Give ‘All’ (read,write/delete,execute) Permissions on the ‘world’ Directory to ‘Everybody’:

   chmod a+rwx $HOME/world

   (Normally Take Care Before to Open a Directory to the World Because this Can Compromise your System Security!)
   Now to Check Permissions Setup:

   ls -l $HOME

   To Remove the ‘Write/Delete’ Permission to the ‘World’:

   chmod a-w $HOME/world

   To Give the ‘Write/Delete’ Permission the ‘world’ Only to the Owner:

   chmod u+w $HOME/world

   To Give the ‘Write/Delete’ Permission the ‘world’ Also to the Owner’s Group:

   chmod g+w $HOME/world

   To Remove the ‘Execution’ Permission to the ‘World’:

   chmod a-x $HOME/world

   To Give the ‘Execution’ Permission to the ‘world’ to the Owner:

   chmod u+x $HOME/world

   To Give the ‘Execution’ Permission to the ‘world’ Also to the Owner’s Group:

   chmod g+x $HOME/world

   (After Only you and your Group will be able to Access the ‘world’ Directory Directory on Shell!)

4. How to Set Ownership on Ubuntu File System

   Ubuntu Setting Ownership Quick Start

   Setting Up Ownership on Ubuntu