以正确格式将getent passwd输出为json

时间：2019-01-18 13:16:27

标签： json linux bash shell format

我正在使用jq尝试将bash命令输出转换为json。但是，转换使我失败了。

使用此行：

hostname && getent passwd | egrep -v '/s?bin/(nologin|shutdown|sync|halt)' | cut -d: -f1 | sudo xargs -I % sh -c  'echo %; chage -l %; echo' | jq --raw-input . | jq --slurp .
  • 主机名必须是json的根元素
  • 用户名必须是第一个元素
  • 获取的passwd输出必须是用户名的子元素

类似这样的事情： JSON

不使用jq的上述命令的输出结果为： Command Output

有人尝试过将bash输出正确转换为json吗？谢谢

2 个答案:

答案 0 :(得分：1)

  

我正在使用jq ...

我意识到jq在这里很受欢迎，但是我建议为此任务推荐Xidel。
尽管Xidel主要是HTML / XML / JSON解析器（使用CSS，XPath，XQuery，JSONiq和模式模板），但Xidel也可以处理基本文本。

您说您想拥有一个像这样的json：

{
  "hostname": "example",
  "users": [
    {
      "username": "example1",
      "details": {
        "LastPasswordChange": "Nov 12, 2018",
        "PasswordExpires": "never",
        "PasswordInactive": "never",
        "AccountExpires": "never",
        "MinDaysBetweenPasswordChange": "0",
        "MaxDaysBetweenPasswordChange": "99999",
        "NumOfDaysOfWarningBeforePasswordExpires": "7"
      }
    },
    {
      "username": "example2",
      "details": {
        "LastPasswordChange": "Nov 13, 2018",
        "PasswordExpires": "never",
        "PasswordInactive": "never",
        "AccountExpires": "never",
        "MinDaysBetweenPasswordChange": "0",
        "MaxDaysBetweenPasswordChange": "99999",
        "NumOfDaysOfWarningBeforePasswordExpires": "7"
      }
    }
  ]
}

这意味着users数组需要为每个用户分别填充对象（从此chage程序的输出创建）。这就是为什么我会选择另一种方法。

假设getent passwd | egrep -v '/s?bin/(nologin|shutdown|sync|halt)' | cut -d: -f1返回：

root
user1
user2

这是我们要传递给Xidel的代码，以首先创建一个基本的json：

getent passwd | egrep -v '/s?bin/(nologin|shutdown|sync|halt)' | cut -d: -f1 | xidel -s - --xquery '
  {
    "hostname":"'$(hostname)'",
    "users":x:lines($raw) ! {
      "username":.
    }
  }
'
  • 在原始命令前不需要hostname &&，因为您只需从Xidel内部调用即可（这也使查询更加容易）。
  • 使用x:lines($raw)，您可以根据Xidel的输入（在本例中为stdin）创建每个新行的序列。可以使用的替代功能为tokenize($raw,"\n")。

查询输出：

{
  "hostname": "user",
  "users": [
    {
      "username": "root"
    },
    {
      "username": "user1"
    },
    {
      "username": "user2"
    }
  ]
}

接下来，我们将在Xidel中调用chage以创建details对象：

getent passwd | egrep -v '/s?bin/(nologin|shutdown|sync|halt)' | cut -d: -f1 | xidel -s - --xquery '
  {
    "hostname":"'$(hostname)'",
    "users":x:lines($raw) ! {
      "username":.,
      "details":{|
        for $x in x:lines(
          system(x"chage -l {.}")
        )
        let $a:=tokenize(
          $x,
          ":"
        )
        return {
          normalize-space($a[1]):normalize-space($a[2])
        }
      |}
    }
  }
'
  • system(x"chage -l {.}")返回chage -l root，chage -l user1和chage -l user2的输出。
  • 在x:lines()周围，您会再次创建每个新行的序列。 user2输出的第一行，例如：
Last password change                                  : Oct 23, 2018
  • 对于此序列（或行）中的每个项目，都会创建变量$a，该变量包含该项目的序列（分为两部分），以:作为分隔符。 $a因此，对于第一项：
Last password change                                  # white-space up untill this point! 
 Oct 23, 2018
  • 最后创建属性-值对，并用空格标准化：
{
  "Last password change": "Oct 23, 2018"
}

查询输出：

{
  "hostname": "user",
  "users": [
    {
      "username": "root",
      "details": {
        "Last password change": "never",
        "Password expires": "never",
        "Password inactive": "never",
        "Account expires": "never",
        "Minimum number of days between password change": "0",
        "Maximum number of days between password change": "99999",
        "Number of days of warning before password expires": "7"
      }
    },
    {
      "username": "user1",
      "details": {
        "Last password change": "never",
        "Password expires": "never",
        "Password inactive": "never",
        "Account expires": "never",
        "Minimum number of days between password change": "0",
        "Maximum number of days between password change": "99999",
        "Number of days of warning before password expires": "7"
      }
    },
    {
      "username": "user2",
      "details": {
        "Last password change": "Oct 23, 2018",
        "Password expires": "never",
        "Password inactive": "never",
        "Account expires": "never",
        "Minimum number of days between password change": "0",
        "Maximum number of days between password change": "99999",
        "Number of days of warning before password expires": "7"
      }
    }
  ]
}

您可以再走一步：

getent passwd | egrep -v '/s?bin/(nologin|shutdown|sync|halt)' | cut -d: -f1 | xidel -s - --xquery '
  {
    "hostname":"'$(hostname)'",
    "users":x:lines($raw) ! {
      "username":.,
      "details":{|
        for $x in x:lines(
          system(x"chage -l {.}")
        )
        let $a:=tokenize(
          $x,
          ":"
        )
        return {
          string-join(
            for $x in tokenize(
              normalize-space($a[1]),
              " "
            )
            return
            upper-case(
              substring(
                $x,
                1,
                1
              )
            )||substring(
              $x,
              2
            )
          ):normalize-space($a[2]) ! (
            if (. castable as decimal) then
              number(.)
            else
              .
          )
        }
      |}
    }
  }
'
  • 使用...
    • 代替Last password change 
string-join(for $x in tokenize(normalize-space($a[1])," ") return upper-case(substring($x,1,1))||substring($x,2))

...它返回：LastPasswordChange。

  • 使用...
    • 代替"99999"（字符串） 
normalize-space($a[2]) ! (if (. castable as decimal) then number(.) else .)

...它返回：99999作为xs：十进制原子类型。

查询输出：

{
  "hostname": "user",
  "users": [
    {
      "username": "root",
      "details": {
        "LastPasswordChange": "never",
        "PasswordExpires": "never",
        "PasswordInactive": "never",
        "AccountExpires": "never",
        "MinimumNumberOfDaysBetweenPasswordChange": 0,
        "MaximumNumberOfDaysBetweenPasswordChange": 99999,
        "NumberOfDaysOfWarningBeforePasswordExpires": 7
      }
    },
    {
      "username": "user1",
      "details": {
        "LastPasswordChange": "never",
        "PasswordExpires": "never",
        "PasswordInactive": "never",
        "AccountExpires": "never",
        "MinimumNumberOfDaysBetweenPasswordChange": 0,
        "MaximumNumberOfDaysBetweenPasswordChange": 99999,
        "NumberOfDaysOfWarningBeforePasswordExpires": 7
      }
    },
    {
      "username": "user2",
      "details": {
        "LastPasswordChange": "Oct 23, 2018",
        "PasswordExpires": "never",
        "PasswordInactive": "never",
        "AccountExpires": "never",
        "MinimumNumberOfDaysBetweenPasswordChange": 0,
        "MaximumNumberOfDaysBetweenPasswordChange": 99999,
        "NumberOfDaysOfWarningBeforePasswordExpires": 7
      }
    }
  ]
}

“美化”查询更容易阅读，但是如果您希望使用“美化”版本：

getent passwd | egrep -v '/s?bin/(nologin|shutdown|sync|halt)' | cut -d: -f1 | xidel -s - --xquery '{"hostname":"'$(hostname)'","users":x:lines($raw) ! {"username":.,"details":{|for $x in x:lines(system(x"chage -l {.}")) let $a:=tokenize($x,":") return {string-join(for $x in tokenize(normalize-space($a[1])," ") return upper-case(substring($x,1,1))||substring($x,2)):normalize-space($a[2]) ! (if (. castable as decimal) then number(.) else .)}|}}}'

答案 1 :(得分：0)

这是一个perl脚本，以JSON格式显示/etc/passwd的主机名和内容（在我熟悉的任何操作系统上，输出看起来都不是您的示例，顺便说一句。）

请注意，在谈论JSON对象的键时，“第一个元素”当然没有任何意义；他们是无序的。如果您依赖于某个特定键位于对象中的特定位置，那么您做错了。

#!/usr/bin/env perl
use warnings;
use strict;
use Sys::Hostname;
use User::pwent;
# Might have to install through your OS's package manager or
# with your favorite CPAN client
use JSON;

my %pwdb = ( hostname => hostname(), users => [] );

while (my $pw = getpwent) {
  # Ignore users with certain shells
  next if
    defined $pw->shell && $pw->shell =~ m!s?bin/(nologin|shutdown|sync|halt)!;
  push @{$pwdb{"users"}}, {
                           username => $pw->name,
                           details => {
                                       passwd => $pw->passwd,
                                       uid => $pw->uid,
                                       gid => $pw->gid,
                                       change => $pw->change,
                                       age => $pw->age,
                                       quota => $pw->quota,
                                       comment => $pw->comment,
                                       class => $pw->class,
                                       gecos => $pw->gecos,
                                       dir => $pw->dir,
                                       shell => $pw->shell,
                                       expire => $pw->expire
                                      }
                          };
}

my $pp = JSON->new->ascii->pretty;
print $pp->encode(\%pwdb);
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