参考: [ Unix & Linux ]
Shell Demo
$echo ${JENKINS_VERSION:-2.7.4}
2.7.4
$JENKINS_VERSION=2.99
$echo ${JENKINS_VERSION:-2.7.4}
2.99
参考: [ Unix & Linux ]
$echo ${JENKINS_VERSION:-2.7.4}
2.7.4
$JENKINS_VERSION=2.99
$echo ${JENKINS_VERSION:-2.7.4}
2.99