Backup using tar

// Create compressed archive
tar -cvzpf <backupfile.tar.gz> <source>

// Create compressed archive excluding files and directories
tar [--exclude='file1.txt'] [--exclude='folder1'] -cvzpf <backupfile.tar.gz> <source>

// Extract archive
tar -xvf file.tar

// Extract compressed archive
tar -xzvf file.tar.gz

// Extract single directory from archive
tar -xzvf file.tar.gz etc

// -c create archive
// -v verbose
// -z compress using gzip
// -p preserve permissions
// -f file
// -x extract

# Show interactive menu to choose php version from
sudo update-alternatives --config php

dig +short myip.opendns.com @resolver1.opendns.com