1. The following command will create all of the following directories ~/a/b/c/d:
a) Mkdir -p ~/a/b/c/d
b) Mkdir ~/a/b/c/d
c) Mkdir -all ~/a/b/c/d
d) Mkdir ~ a b c d
The correct answer is a) Mkdir -p ~/a/b/c/d.
The -p option tells the mkdir command to create any necessary parent directories as well. So in this case, it will create the directories ~/a, ~/a/b, ~/a/b/c, and ~/a/b/c/d if they don't already exist.
Option b) Mkdir ~/a/b/c/d will only create the directory ~/a/b/c/d and will fail if any of the parent directories don't exist.
Option c) Mkdir -all ~/a/b/c/d is not a valid option for the mkdir command.
Option d) Mkdir ~ a b c d is also not a valid option for the mkdir command.