Ubunt 20.04 uses CDROM or ISO as the installation source

Some projects due to security requirements , It needs to be deployed in the intranet without Internet environment , So how to give... In an offline environment ubuntu Installing relevant software is a test for everyone linux It's time for basic knowledge . This article will lead you to use CDROM Or mount ISO The image can be configured in two ways ubuntu20.04 Offline installation source for .
Replace the installation source with cdrom

Use command

mv /etc/apt/sources.list /etc/apt/sources.list.bac
sudo apt-cdrom add

That's all right. .

The above method only supports physical machines with optical drives , And you happen to have ubuntu Operating system DVD Compact disc , If you test in a virtual machine , Then the above method may be problematic .

mount ISO Mirror image

1. Copy ISO file

take ubunt20.04 Mirror image ISO Copy the file to your ubuntu in , Remember the address you copied , Don't copy my .

2. mount ISO file

mount -o loop -t iso9660 /home/alfiy/ubuntu-20.04.1-desktop-amd64.iso  /mnt

3. modify /etc/apt/sources.list file

mv /etc/apt/sources.list /etc/apt/sources.list.bac
echo "deb file:///mnt focal main restricted" > /etc/apt/sources.list

By the command above , my /etc/apt/sources.list It becomes the following file .

Does it look refreshing ？ If your server becomes a networked environment , Don't forget to sources.list.bac Change it back .

4. Update source

apt clean all
apt update

If the prompt in the figure above appears, it indicates ISO The image has been mounted successfully , And as a local installation source .

Let's try installing a software .

apt install -y gcc

If the figure above appears, it indicates that you have attached ISO It's working normally , Quickly install the software you need in the offline environment .