The mkdir command is used to make a new directory. In DOS, OS/2 and Windows, the command is often abbreviated to md.

# Create a directory and all its parents
mkdir -p foo/bar/baz

# Create foo/bar and foo/baz directories
mkdir -p foo/{bar,baz}

# Create the foo/bar, foo/baz, foo/baz/zip and foo/baz/zap directories
mkdir -p foo/{bar,baz/{zip,zap}}