The sources.list file includes the list of packages that can be installed on the system.

Below is an example ubuntu hardy one

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deb http://archive.ubuntu.com/ubuntu hardy main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu hardy-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu hardy-security main restricted universe multiverse
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If you are using Plesk it is a good idea to include the Plesk .deb repository with in the sources.list, below is an example for Plesk
9.3.0

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deb http://autoinstall.plesk.com/ubuntu/PSA_9.3.0/ hardy all
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(you can check what plesk versions are availble by visiting
http://autoinstall.plesk.com/ubuntu/ )




So a complete sources.list file for - Ubuntu hardy - Plesk 9.3.0 would be

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deb http://archive.ubuntu.com/ubuntu hardy main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu hardy-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu hardy-security main restricted universe multiverse
deb http://autoinstall.plesk.com/ubuntu/PSA_9.3.0/ hardy all