Unable to open Software Manager & System Update

[Roakman]

I have just took a backup of one file on my Linux Mint 9 machine by using Terminal. The file name was "sources" and I have used the following command.

    sudo cp /etc/apt/sources /etc/apt/sources_backup

I have seen both the files in the folder "etc" and I guess have made mistake as I am not more able to open Software Manager and I also can't make a system update. It does not seems to be solve this issue manually means removing or replacing the file. Please help!

[SalVatore]

I suggest you to run the following command

    gksudo gedit /etc/apt/sources.list

after which you need to add the corresponding repositories and Save it. here I have provided the default for Mint 9.

    deb http://packages.linuxmint.com/ isadora main upstream import
    deb http://archive.ubuntu.com/ubuntu/ lucid main restricted universe multiverse
    deb http://archive.ubuntu.com/ubuntu/ lucid-updates main restricted universe multiverse
    deb http://security.ubuntu.com/ubuntu/ lucid-security main restricted universe multiverse
    deb http://archive.canonical.com/ubuntu/ lucid partner
    deb http://packages.medibuntu.org/ lucid free non-free

[DanielV]

I guess you have not backup the file properly and because of your mistake there would be two files present in the same directory due to which you are not able to open Software Manager nor you would be able to update system. I suggest you to delete the file that you have just created and then check that it works properly or not. Now you may take backup of the same file at some other place so that your operating system does not gets confused with the existing one.

[Aleksandra]

Here I have provided you the solution that will definitely work for you. use the following command on Terminal.

   sudo bash
    cp /etc/apt/sources.list /etc/apt/sources.list-backup
    gedit /etc/apt/sources.list

Start Editing:
Before:

    deb http://packages.linuxmint.com/ isadora main upstream import
    deb http://archive.ubuntu.com/ubuntu/ lucid main restricted universe multiverse
    deb http://archive.ubuntu.com/ubuntu/ lucid-updates main restricted universe multiverse
    deb http://security.ubuntu.com/ubuntu/ lucid-security main restricted universe multiverse
    deb http://archive.canonical.com/ubuntu/ lucid partner
    deb http://packages.medibuntu.org/ lucid free non-free

After:

    # deb http://packages.linuxmint.com/ isadora main upstream import
    # deb http://archive.ubuntu.com/ubuntu/ lucid main restricted universe multiverse
    # deb http://archive.ubuntu.com/ubuntu/ lucid-updates main restricted universe multiverse
    # deb http://security.ubuntu.com/ubuntu/ lucid-security main restricted universe multiverse
    # deb http://archive.canonical.com/ubuntu/ lucid partner
    # deb http://packages.medibuntu.org/ lucid free non-free

    deb http://packages.linuxmint.com/ julia main upstream import
    deb http://archive.ubuntu.com/ubuntu/ maverick main restricted universe multiverse
    deb http://archive.ubuntu.com/ubuntu/ maverick-updates main restricted universe multiverse
    deb http://security.ubuntu.com/ubuntu/ maverick-security main restricted universe multiverse
    deb http://archive.canonical.com/ubuntu/ maverick partner
    deb http://packages.medibuntu.org/ maverick free non-free

Now save the file and exit from the gedit. Here you would be back in the Terminal and then use following command and then reboot your machine.

    apt-get update
    apt-get dist-upgrade
    apt-get upgrade