如何在Bash中当文本第二列内容变化时打印分隔线

需求说明 #

我通过Ansible playbook查询服务状态得到以下原始数据：

host1  :  zookeeper       :  Active:  active  (running)  since  Wed  2023-02-15  13:57:02  HKT;  2  days   ago
         host2  :  zookeeper       :  Active:  active  (running)  since  Wed  2023-02-15  13:57:01  HKT;  2  days   ago
         host3  :  zookeeper       :  Active:  active  (running)  since  Wed  2023-02-15  13:57:01  HKT;  2  days   ago
         host1  :  Broker          :  Active:  active  (running)  since  Wed  2023-02-15  14:06:53  HKT;  1  day    23h  ago
         host2  :  Broker          :  Active:  active  (running)  since  Wed  2023-02-15  14:07:33  HKT;  1  day    23h  ago
         host3  :  Broker          :  Active:  active  (running)  since  Wed  2023-02-15  14:07:45  HKT;  1  day    23h  ago
         host4  :  Broker          :  Active:  active  (running)  since  Wed  2023-02-15  14:07:52  HKT;  1  day    23h  ago
         host2  :  SchemaRegistry  :  Active:  active  (running)  since  Wed  2023-02-15  14:13:41  HKT;  1  day    23h  ago
         host3  :  SchemaRegistry  :  Active:  active  (running)  since  Wed  2023-02-15  14:15:04  HKT;  1  day    23h  ago
         host4  :  Connect         :  Active:  active  (running)  since  Wed  2023-02-15  14:26:51  HKT;  1  day    23h  ago
         host1  :  ControlCenter   :  Active:  active  (running)  since  Wed  2023-02-15  13:45:09  HKT;  2  days   ago
         host5  :  KSQL            :  Active:  active  (running)  since  Wed  2023-02-15  14:20:28  HKT;  1  day    23h  ago
         host6  :  KSQL            :  Active:  active  (running)  since  Wed  2023-02-15  14:20:28  HKT;  1  day    23h  ago
         host5  :  RestProxy       :  Active:  active  (running)  since  Fri  2023-01-27  22:38:59  HKT;  2  weeks  6    days  ago
         host6  :  RestProxy       :  Active:  active  (running)  since  Wed  2023-02-15  14:31:59  HKT;  1  day    23h  ago

需要将其整理为按服务分组、每组前后插入分隔线的格式，效果如下：

-------------------------------------------------------------------------------------------------
         host1  :  zookeeper       :  Active:  active  (running)  since  Wed  2023-02-15  13:57:02  HKT;  2  days   ago
         host2  :  zookeeper       :  Active:  active  (running)  since  Wed  2023-02-15  13:57:01  HKT;  2  days   ago
         host3  :  zookeeper       :  Active:  active  (running)  since  Wed  2023-02-15  13:57:01  HKT;  2  days   ago
-------------------------------------------------------------------------------------------------
         host1  :  Broker          :  Active:  active  (running)  since  Wed  2023-02-15  14:06:53  HKT;  1  day    23h  ago
         host2  :  Broker          :  Active:  active  (running)  since  Wed  2023-02-15  14:07:33  HKT;  1  day    23h  ago
         host3  :  Broker          :  Active:  active  (running)  since  Wed  2023-02-15  14:07:45  HKT;  1  day    23h  ago
         host4  :  Broker          :  Active:  active  (running)  since  Wed  2023-02-15  14:07:52  HKT;  1  day    23h  ago
-------------------------------------------------------------------------------------------------
         host2  :  SchemaRegistry  :  Active:  active  (running)  since  Wed  2023-02-15  14:13:41  HKT;  1  day    23h  ago
         host3  :  SchemaRegistry  :  Active:  active  (running)  since  Wed  2023-02-15  14:15:04  HKT;  1  day    23h  ago
-------------------------------------------------------------------------------------------------
         host4  :  Connect         :  Active:  active  (running)  since  Wed  2023-02-15  14:26:51  HKT;  1  day    23h  ago
-------------------------------------------------------------------------------------------------
         host1  :  ControlCenter   :  Active:  active  (running)  since  Wed  2023-02-15  13:45:09  HKT;  2  days   ago
-------------------------------------------------------------------------------------------------
         host5  :  KSQL            :  Active:  active  (running)  since  Wed  2023-02-15  14:20:28  HKT;  1  day    23h  ago
         host6  :  KSQL            :  Active:  active  (running)  since  Wed  2023-02-15  14:20:28  HKT;  1  day    23h  ago
-------------------------------------------------------------------------------------------------
         host5  :  RestProxy       :  Active:  active  (running)  since  Fri  2023-01-27  22:38:59  HKT;  2  weeks  6    days  ago
         host6  :  RestProxy       :  Active:  active  (running)  since  Wed  2023-02-15  14:31:59  HKT;  1  day    23h  ago
-------------------------------------------------------------------------------------------------

核心需求：每行第二列（服务名称）变化时，自动插入分隔线。

Bash实现方案 #

可以使用awk工具完成文本处理，以下是具体脚本：

awk -F': ' '
BEGIN {
    sep = "-------------------------------------------------------------------------------------------------"
    print sep
}
{
    current_service = $2
    gsub(/^[[:space:]]+|[[:space:]]+$/, "", current_service)  # 去除服务名前后空格
    if (NR > 1 && current_service != prev_service) {
        print sep
    }
    print $0
    prev_service = current_service
}
END {
    print sep
}
' service_status.txt

脚本说明 #

1. 分隔符设置：用-F': '指定分隔符为: ，这样每行被分割为多个字段，第二字段$2就是服务名称。
2. 初始化：BEGIN块先打印第一条分隔线。
3. 逐行处理：
   • 提取当前行的服务名称，并去除前后多余空格。
   • 如果不是第一行且当前服务名和上一行服务名不同，打印分隔线。
   • 打印当前行内容。
   • 更新上一行服务名为当前服务名。
4. 收尾：END块打印最后一条分隔线。

使用方法 #

1. 将Ansible输出的原始状态数据保存到文件（比如service_status.txt）。
2. 运行上述脚本，即可得到分组带分隔线的格式化输出。
3. 也可以直接通过管道处理Ansible的实时输出，比如：

   ansible-playbook your_playbook.yml | awk -F': ' '
   BEGIN {
       sep = "-------------------------------------------------------------------------------------------------"
       print sep
   }
   {
       current_service = $2
       gsub(/^[[:space:]]+|[[:space:]]+$/, "", current_service)
       if (NR > 1 && current_service != prev_service && $2 != "") {  # 过滤空行或非状态行
           print sep
       }
       if ($2 != "") print $0  # 只输出有效状态行
       prev_service = current_service
   }
   END {
       print sep
   }
   '
   

内容的提问来源于stack exchange，提问作者swapnil kambli