N: Ignoring file 'ros-latest' in directory '/et/apt/sources.list.d/' as it has no filename extention filename extention

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Ignoring file 'ros-latest' in directory '/et/apt/sources.list.d/' as it has no filename extention filename extension

Perhaps surprisingly, this error seems to be pretty explanatory by itself.

The ros-latest file in /etc/apt/sources.list.d is supposed to have a .list extension, and it doesn't on your machine.

If with step 1.4 you are referring to the Installation step in the installation manual, then you may have made a mistake in step 1.2 - Setup your sources:

Setup your computer to accept software from packages.ros.org .

sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'

Notice the .list extension there.

To resolve this, you could do something like the following:

sudo mv /etc/apt/sources.list.d/ros-latest /etc/apt/sources.list.d/ros-latest.list

then try sudo apt-get update again.