" is command prompt like ubuntu@ubuntu
, and it is not a part of the command :-)
Simply run mentioned commands without "example#
ubuntu@ubuntu:~$ ps -ef | grep nautilus
ubuntu@ubuntu:~$ nautilus &
And you don't need "sudo" everytime with every command. Sudo is required only before some admin (i.e. root) level commands/tasks. Whenrver it warns you with message like "you do not have root privilages"
then only use sudo, else it's not needed for every command.