Question

当我执行没有任何标志的“top”命令时，我得到了

使用至少0.1％内存和CPU的十几个进程。

当我使用设置为每分钟运行的cronjob将其打印到文件时，执行下面的命令，但是，我只使用超过0.1％的内存和CPU来获得两个或三个进程。

cronjob执行此命令：

top -b -n 1 | sed -n '8,17p' | sed 's/^ *//' | tr -s ' ' | sed 's/ /", "/g ; s/^/{"/g ; s/$/"},/g ; 1s/^/[/ ; $ s/.$/]/ ; s/"/"pid": "/1 ; s/"/"user": "/5 ; s/"/"pr": "/9 ; s/"/"ni": "/13 ; s/"/"virt": "/17 ; s/"/"res": "/21 ; s/"/"shr": "/25 ; s/"/"s": "/29 ; s/"/"cpu": "/33 ; s/"/"mem": "/37 ; s/"/"time": "/41 ; s/"/"command": "/45 ; s/"$-\?[0-9]\+$"/\1/g'

以批处理模式获取“top”的第一帧并以JSON格式返回，例如像这样的东西：

[
    {
        "pid": 7303,
        "user": "fahclie+",
        "pr": 39,
        "ni": 19,
        "virt": 255736,
        "res": 14716,
        "shr": 5556,
        "s": "S",
        "cpu": "400,9",
        "mem": "0,2",
        "time": "210:15.98",
        "command": "FahCore_a4"
    },
    {
        "pid": 1,
        "user": "root",
        "pr": 20,
        "ni": 0,
        "virt": 42040,
        "res": 4664,
        "shr": 2840,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,1",
        "time": "0:01.16",
        "command": "init"
    },
    {
        "pid": 2,
        "user": "root",
        "pr": 20,
        "ni": 0,
        "virt": 0,
        "res": 0,
        "shr": 0,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,0",
        "time": "0:00.00",
        "command": "kthreadd"
    },
    {
        "pid": 3,
        "user": "root",
        "pr": 20,
        "ni": 0,
        "virt": 0,
        "res": 0,
        "shr": 0,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,0",
        "time": "0:00.13",
        "command": "ksoftirqd/0"
    },
    {
        "pid": 5,
        "user": "root",
        "pr": 0,
        "ni": -20,
        "virt": 0,
        "res": 0,
        "shr": 0,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,0",
        "time": "0:00.00",
        "command": "kworker/0:+"
    },
    {
        "pid": 7,
        "user": "root",
        "pr": 20,
        "ni": 0,
        "virt": 0,
        "res": 0,
        "shr": 0,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,0",
        "time": "0:03.58",
        "command": "rcu_sched"
    },
    {
        "pid": 8,
        "user": "root",
        "pr": 20,
        "ni": 0,
        "virt": 0,
        "res": 0,
        "shr": 0,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,0",
        "time": "0:00.00",
        "command": "rcu_bh"
    },
    {
        "pid": 9,
        "user": "root",
        "pr": 20,
        "ni": 0,
        "virt": 0,
        "res": 0,
        "shr": 0,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,0",
        "time": "0:01.26",
        "command": "rcuos/0"
    },
    {
        "pid": 10,
        "user": "root",
        "pr": 20,
        "ni": 0,
        "virt": 0,
        "res": 0,
        "shr": 0,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,0",
        "time": "0:00.00",
        "command": "rcuob/0"
    },
    {
        "pid": 11,
        "user": "root",
        "pr": "rt",
        "ni": 0,
        "virt": 0,
        "res": 0,
        "shr": 0,
        "s": "S",
        "cpu": "0,0",
        "mem": "0,0",
        "time": "0:00.51",
        "command": "migration/0"
    }

]

请注意，从第三个进程开始，这些进程中没有一个使用超过0.0％的内存或CPU。

我怀疑这是因为top的第一帧是正在写的那一帧，而在第一帧中，top仍在收集过程信息。

有没有办法将第二帧打印到文件中？

Answer 1

我在freenode的#bash IRC频道中找到了答案，感谢jamesd：

首先我们使用top -b -n 2返回前2帧。

然后我们将这些帧管道传输到grep -A10 'PID USER'（10是匹配行之后的尾随上下文行数，'PID USER'标题行的开头），然后管道这样做的结果是tail -n 10摆脱标题行。

这仅显示top的第二帧的前10个进程。

10当然可以替换为所需的进程数量，'PID USER'可以替换个人top配置标题行中的第一个字段。

打印顶部输出的第二帧

1 个答案: