중복 저장소를 제거하는 방법은 무엇입니까?

sudo apt-get install 작업을 수행할 때 이 문제가 몇 번 발생했습니다.

이는 문제가 있음을 알려주는 출력 부분입니다.

W: Duplicate sources.list entry http...://security.ubuntu.com/ubuntu/ trusty-security/multiverse amd64 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_multiverse_binary-amd64_Packages)
W: Duplicate sources.list entry http...://security.ubuntu.com/ubuntu/ trusty-security/restricted amd64 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_restricted_binary-amd64_Packages)
W: Duplicate sources.list entry http...://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_main_binary-amd64_Packages)
W: Duplicate sources.list entry http...://security.ubuntu.com/ubuntu/ trusty-security/universe amd64 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_universe_binary-amd64_Packages)
W: Duplicate sources.list entry http...://security.ubuntu.com/ubuntu/ trusty-security/multiverse i386 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_multiverse_binary-i386_Packages)
W: Duplicate sources.list entry http...://security.ubuntu.com/ubuntu/ trusty-security/restricted i386 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http...://security.ubuntu.com/ubuntu/ trusty-security/main i386 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_main_binary-i386_Packages)
W: Duplicate sources.list entry http...://security.ubuntu.com/ubuntu/ trusty-security/universe i386 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_universe_binary-i386_Packages)
W: You may want to run apt-get update to correct these problems

어떤 ppa가 이 문제를 일으키는지 모르겠습니다. 누구든지 문제가 어디에 있는지 확인할 수 있습니까?

이는 다음의 출력입니다.

cat /etc/apt/sources.list  

# deb cdrom:[elementary OS 0.3 _Freya_ - Stable amd64 (20150411)]/ trusty main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://il.archive.ubuntu.com/ubuntu/ trusty main restricted
deb-src http://il.archive.ubuntu.com/ubuntu/ trusty main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://il.archive.ubuntu.com/ubuntu/ trusty-updates restricted main
deb-src http://il.archive.ubuntu.com/ubuntu/ trusty-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://il.archive.ubuntu.com/ubuntu/ trusty universe
deb-src http://il.archive.ubuntu.com/ubuntu/ trusty universe
deb http://il.archive.ubuntu.com/ubuntu/ trusty-updates universe
deb-src http://il.archive.ubuntu.com/ubuntu/ trusty-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://il.archive.ubuntu.com/ubuntu/ trusty multiverse
deb-src http://il.archive.ubuntu.com/ubuntu/ trusty multiverse
deb http://il.archive.ubuntu.com/ubuntu/ trusty-updates multiverse
deb-src http://il.archive.ubuntu.com/ubuntu/ trusty-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
# deb http://il.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
# deb-src http://il.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu trusty-security main restricted
deb-src http://security.ubuntu.com/ubuntu trusty-security main restricted
deb http://security.ubuntu.com/ubuntu trusty-security universe
deb-src http://security.ubuntu.com/ubuntu trusty-security universe
deb http://security.ubuntu.com/ubuntu trusty-security multiverse
deb-src http://security.ubuntu.com/ubuntu trusty-security multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu trusty partner
deb-src http://archive.canonical.com/ubuntu trusty partner

## Uncomment the following two lines to add software from Ubuntu's
## 'extras' repository.
## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu trusty main
deb-src http://extras.ubuntu.com/ubuntu trusty main
deb http://security.ubuntu.com/ubuntu/ trusty-security multiverse restricted main universe
deb http://liveusb.info/multisystem/depot all main
deb-src http://liveusb.info/multisystem/depot all main  

이는 다음의 출력입니다.

ls -l /etc/apt/sources.list.d/  
total 32
-rw-r--r-- 1 root root  69 אפר 22 20:16 elementary.list
-rw-r--r-- 1 root root  69 אפר 22 20:16 elementary.list.save
-rw-r--r-- 1 root root   0 אפר 14 12:49 elementary-os-daily-trusty.list
-rw-r--r-- 1 root root   0 אפר 14 12:49 elementary-os-daily-trusty.list.save
-rw-r--r-- 1 root root   0 אפר 22 20:05 elementary-os-stable-trusty.list
-rw-r--r-- 1 root root   0 אפר 22 20:05 elementary-os-stable-trusty.list.save
-rw-r--r-- 1 root root   0 אפר 22 20:06 mc3man-trusty-media-trusty.list
-rw-r--r-- 1 root root   0 אפר 22 20:06 mc3man-trusty-media-trusty.list.save
-rw-r--r-- 1 root root   0 אפר 22 20:05 mpstark-elementary-tweaks-daily-trusty.list
-rw-r--r-- 1 root root   0 אפר 22 20:05 mpstark-elementary-tweaks-daily-trusty.list.save
-rw-r--r-- 1 root root 150 אפר 22 20:16 patches.list
-rw-r--r-- 1 root root 150 אפר 22 20:16 patches.list.save
-rw-r--r-- 1 root root 158 אפר 22 20:16 varlesh-l-ppa-elementary-add-trusty.list
-rw-r--r-- 1 root root 158 אפר 22 20:16 varlesh-l-ppa-elementary-add-trusty.list.save
-rw-r--r-- 1 root root 158 אפר 22 20:16 versable-elementary-update-trusty.list
-rw-r--r-- 1 root root 156 אפר 22 20:16 versable-elementary-update-trusty.list.save