Requirements

This method works best with a connected computer with same OS and Version.
This enables one to ascertain the dependent packages that need to be downloaded by the Package Manager for the disconnected (air-gapped) computer.

sudo will only be used when necessary.

Centos 7 Example

On Redhat and Centos OS, tar and libnsl may need to be installed as they are needed to unpack the installer runfile.

Debian 9 Example

On Debian and Ubuntu OS, tar, which is normally installed by default, may need to be installed as it is needed to unpack the installer runfile.