tail 一般用于查看日志等操作。使用如下：

    1. tail [参数] [文件]

    参数如下：

    1. -f 循环读取
    2. -q 不显示处理信息
    3. -c<数目> 显示的字节数
    4. -n<行数> 显示文件的尾部 n 行内容
    5. --pid=PID 与-f合用,表示在进程ID,PID死掉之后结束
    6. -q, --quiet, --silent 从不输出给出文件名的首部
    7. -s, --sleep-interval=S 与-f合用,表示在每次反复的间隔休眠S秒

    例如一个日志文件ceshi.log如下：

    1. 4234 2019-09-04 17:08:58,097 PublishManager.py searchCfgFile:90 DEBUG publish id 1 relate file record is:7
    2. 4234 2019-09-04 17:08:58,107 PublishManager.py searchCfgFile:90 DEBUG publish id 2 relate file record is:0
    3. 4234 2019-09-04 17:08:58,110 PublishManager.py searchCfgFile:90 DEBUG publish id 3 relate file record is:0
    4. 4234 2019-09-04 17:08:58,112 PublishManager.py searchCfgFile:90 DEBUG publish id 4 relate file record is:0
    5. 4234 2019-09-04 17:08:58,114 PublishManager.py searchCfgFile:90 DEBUG publish id 5 relate file record is:0
    6. 4234 2019-09-04 17:08:58,118 PublishManager.py searchCfgFile:90 DEBUG publish id 6 relate file record is:0
    7. 4234 2019-09-04 17:08:58,121 PublishManager.py searchCfgFile:90 DEBUG publish id 7 relate file record is:0
    8. 4234 2019-09-04 17:08:58,124 PublishManager.py searchCfgFile:90 DEBUG publish id 8 relate file record is:0
    9. 4234 2019-09-04 17:08:58,127 PublishManager.py searchCfgFile:90 DEBUG publish id 9 relate file record is:0
    10. 4234 2019-09-04 17:08:58,130 PublishManager.py searchCfgFile:90 DEBUG publish id 10 relate file record is:0
    11. 4234 2019-09-04 17:08:58,133 PublishManager.py searchCfgFile:90 DEBUG publish id 11 relate file record is:0
    12. 4234 2019-09-04 17:08:58,136 PublishManager.py searchCfgFile:90 DEBUG publish id 12 relate file record is:0
    13. 4234 2019-09-04 17:08:58,138 PublishManager.py searchCfgFile:90 DEBUG publish id 13 relate file record is:0
    14. 4234 2019-09-04 17:08:58,141 PublishManager.py searchCfgFile:90 DEBUG publish id 14 relate file record is:0
    15. 4234 2019-09-04 17:08:58,144 PublishManager.py searchCfgFile:90 DEBUG publish id 15 relate file record is:0
    16. 4234 2019-09-04 17:08:58,147 PublishManager.py searchCfgFile:90 DEBUG publish id 16 relate file record is:0
    17. 4234 2019-09-04 17:08:58,150 PublishManager.py searchCfgFile:90 DEBUG publish id 17 relate file record is:0
    1. tail ceshi.log
    2. # 结果 只显示了最后十行
    3. 4234 2019-09-04 17:08:58,124 PublishManager.py searchCfgFile:90 DEBUG publish id 8 relate file record is:0
    4. 4234 2019-09-04 17:08:58,127 PublishManager.py searchCfgFile:90 DEBUG publish id 9 relate file record is:0
    5. 4234 2019-09-04 17:08:58,130 PublishManager.py searchCfgFile:90 DEBUG publish id 10 relate file record is:0
    6. 4234 2019-09-04 17:08:58,133 PublishManager.py searchCfgFile:90 DEBUG publish id 11 relate file record is:0
    7. 4234 2019-09-04 17:08:58,136 PublishManager.py searchCfgFile:90 DEBUG publish id 12 relate file record is:0
    8. 4234 2019-09-04 17:08:58,138 PublishManager.py searchCfgFile:90 DEBUG publish id 13 relate file record is:0
    9. 4234 2019-09-04 17:08:58,141 PublishManager.py searchCfgFile:90 DEBUG publish id 14 relate file record is:0
    10. 4234 2019-09-04 17:08:58,144 PublishManager.py searchCfgFile:90 DEBUG publish id 15 relate file record is:0
    11. 4234 2019-09-04 17:08:58,147 PublishManager.py searchCfgFile:90 DEBUG publish id 16 relate file record is:0
    12. 4234 2019-09-04 17:08:58,150 PublishManager.py searchCfgFile:90 DEBUG publish id 17 relate file record is:0
    14. tail -f ceshi.log
    15. # 结果
    16. 4234 2019-09-04 17:08:58,124 PublishManager.py searchCfgFile:90 DEBUG publish id 8 relate file record is:0
    17. 4234 2019-09-04 17:08:58,127 PublishManager.py searchCfgFile:90 DEBUG publish id 9 relate file record is:0
    18. 4234 2019-09-04 17:08:58,130 PublishManager.py searchCfgFile:90 DEBUG publish id 10 relate file record is:0
    19. 4234 2019-09-04 17:08:58,133 PublishManager.py searchCfgFile:90 DEBUG publish id 11 relate file record is:0
    20. 4234 2019-09-04 17:08:58,136 PublishManager.py searchCfgFile:90 DEBUG publish id 12 relate file record is:0
    21. 4234 2019-09-04 17:08:58,138 PublishManager.py searchCfgFile:90 DEBUG publish id 13 relate file record is:0
    22. 4234 2019-09-04 17:08:58,141 PublishManager.py searchCfgFile:90 DEBUG publish id 14 relate file record is:0
    23. 4234 2019-09-04 17:08:58,144 PublishManager.py searchCfgFile:90 DEBUG publish id 15 relate file record is:0
    24. 4234 2019-09-04 17:08:58,147 PublishManager.py searchCfgFile:90 DEBUG publish id 16 relate file record is:0
    25. 4234 2019-09-04 17:08:58,150 PublishManager.py searchCfgFile:90 DEBUG publish id 17 relate file record is:0
    26. #这里可以看到光标还在进行，log文件有更新，这里会继续输出
    27. # 我们新建一个终端追加内容进ceshi.log文件看看
    28. echo 'this is test log' >> ./ceshi.log
    29. # 这是我们可以看到，光标下面新出现了一行
    30. this is test log
    32. tail -q ceshi.log
    33. # 结果， 这个参数没弄明白
    34. 4234 2019-09-04 17:08:58,127 PublishManager.py searchCfgFile:90 DEBUG publish id 9 relate file record is:0
    35. 4234 2019-09-04 17:08:58,130 PublishManager.py searchCfgFile:90 DEBUG publish id 10 relate file record is:0
    36. 4234 2019-09-04 17:08:58,133 PublishManager.py searchCfgFile:90 DEBUG publish id 11 relate file record is:0
    37. 4234 2019-09-04 17:08:58,136 PublishManager.py searchCfgFile:90 DEBUG publish id 12 relate file record is:0
    38. 4234 2019-09-04 17:08:58,138 PublishManager.py searchCfgFile:90 DEBUG publish id 13 relate file record is:0
    39. 4234 2019-09-04 17:08:58,141 PublishManager.py searchCfgFile:90 DEBUG publish id 14 relate file record is:0
    40. 4234 2019-09-04 17:08:58,144 PublishManager.py searchCfgFile:90 DEBUG publish id 15 relate file record is:0
    41. 4234 2019-09-04 17:08:58,147 PublishManager.py searchCfgFile:90 DEBUG publish id 16 relate file record is:0
    42. 4234 2019-09-04 17:08:58,150 PublishManager.py searchCfgFile:90 DEBUG publish id 17 relate file record is:0
    43. this is test log
    45. tail -c 10 ceshi.log
    46. # 结果 显示最后十个字节
    47.  test log
    49. tail -n 1 ceshi.log
    50. # 结果 显示最后一行内容
    51. this is test log
    53. tail +15 ceshi.log
    54. # 结果 从第15行到最后
    55. 4234 2019-09-04 17:08:58,144 PublishManager.py searchCfgFile:90 DEBUG publish id 15 relate file record is:0
    56. 4234 2019-09-04 17:08:58,147 PublishManager.py searchCfgFile:90 DEBUG publish id 16 relate file record is:0
    57. 4234 2019-09-04 17:08:58,150 PublishManager.py searchCfgFile:90 DEBUG publish id 17 relate file record is:0
    58. this is test log