Generate a full Package.xml using the Salesforce CLI new mdapi commands
$ GenerateFullPackageXML.sh <APIVERSION> <OUTPUTFILE> <ORGALIAS> <RESTRICTEDMEDATADAFILENAME(Optional)>
Example
$ GenerateFullPackageXML.sh 45.0 ./Package.xml OrgAlias
$ GenerateFullPackageXML.sh 45.0 ./Package.xml OrgAlias filename.txt