problemas na execucao

fiz a instalacao do node e do npm, depois instalei o angular. estas sao as versoes:

cobra@Cobra:~$ node -v
v10.16.0
cobra@Cobra:~$ npm -v
6.9.0
cobra@Cobra:~$ ng version

_ _ ____ _ ___
/ \ _ __ __ _ _ _| | __ _ _ __ / ___| | |_ _|
/ △ \ | '_ \ / _` | | | | |/ _` | '__| | | | | | |
/ ___ \| | | | (_| | |_| | | (_| | | | |___| |___ | |
/_/ \_\_| |_|\__, |\__,_|_|\__,_|_| \____|_____|___|
|___/


Angular CLI: 8.1.1
Node: 10.16.0
OS: linux x64
Angular:
...

mas quando tento fazer um novo projeto da esse erro:

npm ERR! cb() never called!

npm ERR! This is an error with npm itself. Please report this error at:
npm ERR! <https://npm.community>;
Package install failed, see above.