How to remove repositories on Ubuntu 16.04

How to remove repositories on Ubuntu 16.04

In an effort to install various apps in Ubuntu or other Linux distribution, we often add several PPA. Most of the times these PPAs are managed by a single developer as he might have created a certain app for personal insterest or as a hobby. These PPAs may not be updated on the part of latest operating system. This might cause trouble when you are trying to update your OS. You may have other reasons as well for deleting or removing a PPA from the source list.

To remove repositories

To remove unwanted repositories, type the following command

root@linuxhelp:~#  add-apt-repository ppa:cairo-dock-team/weekly
 Contains packages for the UNSTABLE release of Cairo-Dock (Weekly Build or even multiple builds per week)
Stable release are available there : https://launchpad.net/~cairo-dock-team/+archive/ppa
== How to use it ==
The ppa : Execute this in terminal:
    sudo -v
    echo " deb http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu $(lsb_release -sc) main ## Cairo-Dock-PPA"  | sudo tee -a /etc/apt/sources.list
    sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E80D6BF5
    sudo apt-get update
The installation : Execute this in terminal:
    sudo apt-get install cairo-dock cairo-dock-plug-ins
== Info ==
  Launchpad page : https://launchpad.net/cairo-dock
  Website : http://www.glx-dock.org
 More info: https://launchpad.net/~cairo-dock-team/+archive/ubuntu/weekly
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keyring `/tmp/tmp3r9tpkws/secring.gpg'  created
gpg: keyring `/tmp/tmp3r9tpkws/pubring.gpg'  created
gpg: requesting key E80D6BF5 from hkp server keyserver.ubuntu.com
gpg: /tmp/tmp3r9tpkws/trustdb.gpg: trustdb created
gpg: key E80D6BF5: public key " Launchpad cairo-dock"  imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)
OK

Update the apt resources

To update the apt resources after removing the repositories.

root@linuxhelp:~# apt-get update
Hit:1 http://security.ubuntu.com/ubuntu xenial-security InRelease
Hit:2 http://in.archive.ubuntu.com/ubuntu xenial InRelease
Ign:3 http://ppa launchpad.net/cairo-dock-team/weekly/ubuntu xenial InRelease
Hit:4 http://ppa.launchpad.net/minecraft-installer-peeps/minecraft-installer/ubuntu xenial InRelease
Hit:5 http://in.archive.ubuntu.com/ubuntu xenial-updates InRelease            
Hit:6 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial InRelease       
Hit:7 http://in.archive.ubuntu.com/ubuntu xenial-backports InRelease          
Ign:8 http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial Release   
Hit:9 http://repository.spotify.com stable InRelease                   
Ign:10 http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial/main amd64 Packages
Ign:11 http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial/main i386 Packages
Ign:12 http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial/main all Packages
.
.
.
Ign:13 http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial/main Translation-en_IN
Ign:14 http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial/main Translation-en
Ign:15 http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:16 http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial/main DEP-11 64x64 Icons
Reading package lists... Done
W: The repository ' http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu xenial Release'  does not have a Release file.
N: Data from such a repository can' t be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://ppa.launchpad.net/cairo-dock-team/weekly/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.

You can use add-apt-repository command with “ --remove” option like below.

root@linuxhelp:~# add-apt-repository --remove ppa:cairo-dock-team/weekly

Or you can also remove the repo graphically.

Click and search the software and updates and click it.

And select ' Other software' tab.

And remove the tick mark on unwanted repo link.

And click close

Click reload to reload the caches.

Now its reloaded.

After that update your apt source.

root@linuxhelp:~# apt-get update
Hit:1 http://ppa.launchpad.net/minecraft-installer-peeps/minecraft-installer/ubuntu xenial InRelease
Get:2 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]    
Hit:3 http://in.archive.ubuntu.com/ubuntu xenial InRelease                    
Hit:4 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial InRelease       
Hit:5 http://in.archive.ubuntu.com/ubuntu xenial-updates InRelease            
Get:6 http://in.archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB] 
Hit:7 http://repository.spotify.com stable InRelease                          
Fetched 204 kB in 1s (136 kB/s)                                               
Reading package lists... Done

Now the respective repos are removed successfully.