子shell 控制变量
ansible-direc:~ # (export hello=world;echo $hello)
world
ansible-direc:~ # echo $hello
ansible-direc:~ #
实例： 不用单独更改权限，局部变量生效创建ca证书的私钥
ansible-direc:/etc/pki/CA # (umask 077;openssl genrsa -out private/cakey.pem 2048)
Generating RSA private key, 2048 bit long modulus
.+++
.........................................................................+++
e is 65537 (0x10001)