sudo apt-get update
sudo apt-get upgrade
sudo apt install clang libicu-dev libpython2.7-dev libtinfo5 libncurses5 libpython2.7 libz3-dev
wget https://download.swift.org/swift-5.6.1-release/ubuntu2004/swift-5.6.1-RELEASE/swift-5.6.1-RELEASE-ubuntu20.04.tar.gz
tar xzf swift-5.6.1-RELEASE-ubuntu20.04.tar.gz
rm -f swift-5.6.1-RELEASE-ubuntu20.04.tar.gz
sudo mv swift-5.6.1-RELEASE-ubuntu20.04 /usr/share/swift
echo 'export PATH=/usr/share/swift/usr/bin:$PATH' >> ~/.bashrc
source ~/.bashrc
$ swift --version
Swift version 5.6.1 (swift-5.6.1-RELEASE)
Target: x86_64-unknown-linux-gnu
$ swift
Welcome to Swift version 5.6.1 (swift-5.6.1-RELEASE).
Type :help for assistance.
1>
1> print("Hello World!")
Hello World!
2>