How to install Kicad 5.15 by use local repository way? - repository

Question

I have installed Kicad 5.15 on my computer and it works fine, and I have saved all the deb files downloaded during the last installation and put them in /var/cache/apt/archives, when I need to reinstall, I just need to execute these commands:
sudo add-apt-repository --yes ppa:js-reynaud/kicad-5.1
sudo apt update
sudo apt install --install-recommends kicad
The installation will start automatically, and because of the existence of the deb files, the installation process does not require an Internet connection and is very fast. However, this method does not work after the Kicad provide a latest version update, and the installation process will still access the network to download new files. I don't want to do this, one of the reasons is that I have a slow internet access and I'm not used to frequently updating software versions. So I made a local APT source according to the online materials, the method is as follows:
sudo apt install dpkg-dev
sudo mkdir /var/debs
sudo cp /var/cache/apt/archives/*.deb /var/debs/
sudo chmod 777 /var/debs
sudo cd /var/debs
sudo dpkg-scanpackages . /dev/null | gzip -9c > Packages.gz
Then I add a line in Sources.list file
deb file:/var/debs ./
I referenced this page How to create a local APT repository?
But this method does not work. When I run
sudo apt update
I got this:
sudo apt update
Get:1 file:/var/debs ./ InRelease
Ign:1 file:/var/debs ./ InRelease
Get:2 file:/var/debs ./ Release
Err:2 file:/var/debs ./ Release
File not found - /var/debs/./Release (2: No such file or directory)
Reading package lists... Done
E: The repository 'file:/var/debs ./ Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
When I run the installation command, the prompt is as follows:
sudo apt install --install-recommends kicad
E: Malformed entry 76 in list file /etc/apt/sources.list (Suite)
E: The list of sources could not be read.
E: Malformed entry 76 in list file /etc/apt/sources.list (Suite)
E: The list of sources could not be read.
Did I miss something? What should I do to continue using the DEB files saved on my hard drive?

Answer 1

Just add [trusted=yes] to your sources.list file:
deb [trusted=yes] file:/var/debs ./