1. 分支

if cond;then
  commands
fi

if cond;then
  commands1
else
  commands2
fi

if cond1;then
  commands1
elif cond2;then
  commands2
else
  commands3
fi

case value in
  case1)
    commands1
  case2)
    commands2
esac

2. 循环

while cond;do
  commands
done

util cond;do
  commands
done

for var in list;do
  commands
done

3. 函数

[ function ] funname [()]
{
  commands;
  [return int]
}

4. 模块引用

. /path/module.sh
source /path/module.sh

shell--基本语法