sudo apt-get install firmware-iwlwifi
Reading package lists... Done
Building dependency tree       
Reading state information... Done
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/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 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/restricted i386 Packages (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_restricted_binary-i386_Packages)
W: You may want to run apt-get update to correct these problems
E: Unable to locate package firmware-iwlwifi