. shell逻辑表达式
#!/bin/bash
FILE_BASED_ENCRYPTION="true"
if [ "$FILE_BASED_ENCRYPTION" == "true" ]
then
echo "if: first one" || echo "if: second one"
else
echo "else case"
fi
echo "if: first one"执行的返回值是0（为真），所以||后面的echo "if: second one"不会执行了
原文：https://www.cnblogs.com/aspirs/p/14593672.html