python将\ n作为\ x0a传递给bash命令行

时间:2014-06-11 07:53:35

标签: python linux bash python-2.7 escaping

所以我试图将命令从python传递到命令行作为hex换行符: \ x0a 在python中也称为" \ n "

我尝试通过命令行打印的是:

  

check_nrpe -H 127.0.0.1 -c check_users -a" echo -e "\x0a ls "#" 4 4

我试过

import subprocess as sb
sb.check_call(["check_nrpe", \ # first argument
               "-H", host, # host
               "-c", "check_users", # wanted remote command
               "-a", # option
               "\"`echo -e", 
               "\"\\x0a", # <new line>, problem is that python changes this to \n 
               parameter,
               "\"` #\"", "4", "4"]])

&#34; \&#34; \ x0a&#34; #,问题是python在将参数传递给命令行时将其更改为 \ n

所以我要做的是打印 \ x0a 而不是 \ n

我也尝试编码

  "\n".encode("hex")
  which prints "0a"

问题是我如何告诉python将参数\ x0a传递给命令行。

1 个答案:

答案 0 :(得分:0)

澄清您的check_nrpe来电

假设你安装了Nagios(我有它并运行Ubuntu)

cd /urs/lib/nagios/plugins

请参阅check_nrpe帮助

$ ./check_nrpe -h

NRPE Plugin for Nagios
Copyright (c) 1999-2008 Ethan Galstad (nagios@nagios.org)
Version: 2.12
Last Modified: 03-10-2008
License: GPL v2 with exemptions (-l for more info)
SSL/TLS Available: Anonymous DH Mode, OpenSSL 0.9.6 or higher required

Usage: check_nrpe -H <host> [-n] [-u] [-p <port>] [-t <timeout>] [-c <command>] [-a <arglist...>]

Options:
 -n         = Do no use SSL
 -u         = Make socket timeouts return an UNKNOWN state instead of CRITICAL
 <host>     = The address of the host running the NRPE daemon
 [port]     = The port on which the daemon is running (default=5666)
 [timeout]  = Number of seconds before connection times out (default=10)
 [command]  = The name of the command that the remote daemon should run
 [arglist]  = Optional arguments that should be passed to the command.  Multiple
              arguments should be separated by a space.  If provided, this must be
              the last option supplied on the command line.
 -h,--help    Print this short help.
 -l,--license Print licensing information.
 -n,--no-ssl  Do not initial an ssl handshake with the server, talk in plaintext.

Note:
This plugin requires that you have the NRPE daemon running on the remote host.
You must also have configured the daemon to associate a specific plugin command
with the [command] option you are specifying here.  Upon receipt of the
[command] argument, the NRPE daemon will run the appropriate plugin command and
send the plugin output and return code back to *this* plugin.  This allows you
to execute plugins on remote hosts and 'fake' the results to make Nagios think
the plugin is being run locally.

检查您的示例通话(我已更正原始帖子中丢失的格式,它隐藏了反引号):

$ check_nrpe -H 127.0.0.1 -c check_users -a "`echo -e "\x0a ls "` #" 4 4

您似乎尝试调用check_users命令并传递一些参数。因此,远程(NRPE驱动)机器的最终调用将如下所示:

$ check_users "`echo -e "\x0a ls "` #" 4 4

将其与帮助屏幕上check_users建议的内容进行比较:

$ ./check_users -h
check_users v1.4.15 (nagios-plugins 1.4.15)
Copyright (c) 1999 Ethan Galstad
Copyright (c) 2000-2007 Nagios Plugin Development Team
        <nagiosplug-devel@lists.sourceforge.net>

This plugin checks the number of users currently logged in on the local
system and generates an error if the number exceeds the thresholds specified.


Usage:
check_users -w <users> -c <users>

Options:
 -h, --help
    Print detailed help screen
 -V, --version
    Print version information
 -w, --warning=INTEGER
    Set WARNING status if more than INTEGER users are logged in
 -c, --critical=INTEGER
    Set CRITICAL status if more than INTEGER users are logged in

Send email to nagios-users@lists.sourceforge.net if you have questions
regarding use of this software. To submit patches or suggest improvements,
send email to nagiosplug-devel@lists.sourceforge.net

很明显,您check_users超过check_nrpe的尝试被打破,因为check_users预计恰好有四个参数,并且调用应该是这样的(假设您认为4个用户都是关键的警告级别):

$ ./check_users -c 4 -w 4

所以check_nrpe的最终通话可能如下:

$ check_nrpe -H 127.0.0.1 -c check_users -a -c 4 -w 4

注意,如果您尝试将动态值传递给critical和warning,则应该通过Nagios变量执行此操作,并且不要假设它将由命令行(在远程计算机上发生)进行整形。这种技术可行,但相当棘手。

将换行符或其他字符传递给命令行调用

另一个主题是,如何将换行符或其他特殊字符传递给Python的命令。

这里并不是那么困难,因为你有机会传递一个参数列表,这些参数列表不会被shell解释,而是直接传递给命令。

简单命令行脚本bcmd.py

以下脚本允许测试从命令行传递的参数:

import sys
print sys.argv

从Python代码

调用命令的测试
from subprocess import call

args = ["python", "bcmd.py"]
args.append("alfa")
args.append("be\nta")
args.append("""gama
        hama""")
args.append("omega\x0aOMEGA")
args.append("double-omega\x0adouble-OMEGA")
args.append("literaly\\x0aliteraly")

call(args)

称之为:

$ python callit.py 
['bcmd.py', 'alfa', 'be\nta', 'gama\n        hama', 'omega\nOMEGA', 'double-omega\ndouble-OMEGA', 'literaly\\x0aliteraly']

并从中学习。

结论:

  • Python允许调用命令并通过列表绕过shell解析规则传递参数。
  • 在你的情况下,真正的问题似乎是使用check_nrpe而不是传递换行符。