Create RPM build environment CentOS 6/7
 # yum -y groupinstall "Development Tools"
 # yum install epel-release rpmdevtools mock
 # useradd build
 # passwd build
 # visudo 
   Under 
        root   ALL=(ALL)	ALL
   Add	 
        build   ALL=(ALL)       ALL
 $ su - build
 $ rpmdev-setuptree

 Command: mkdir
 # mkdir options <dir>
 Examples:
 # mkdir myProject
 # mkdir -p myProject/{src,doc,tools,db}
 # mkdir -p myProject/{src,doc/{api,system},tools,db}