python - 解析\在命令行参数 - python 2.7.3

Question

我正在从 bash 调用 python 脚本 parse_input.py

parse_input.py 采用命令行参数，其中包含许多 '\n' 字符。

示例输入:

$ python parse_input.py "1\n2\n"

import sys
import pdb

if __name__ == "__main__":

    assert(len(sys.argv) == 2)

    data =  sys.argv[1]
    pdb.set_trace()
    print data

我可以在 pdb 上看到 `data = "1\\n2\\n" 而我想要 data="1\n2\n"

我看到类似的行为只有 \(没有 \n)被 \\

取代

如何删除多余的 \ ？

我不希望脚本处理额外的 \ 作为也可以从文件接收相同的输入。

bash 版本:GNU bash，版本 4.2.24(1)-release (i686-pc-linux-gnu)

python 版本:2.7.3

Answer 1

Bash 不解释常规单引号和双引号字符串中的转义字符。要让它解释(某些)转义字符，您可以使用 $'...':

   Words of the form $'string' are treated specially.  The word expands to
   string, with backslash-escaped characters replaced as specified by  the
   ANSI  C  standard.  Backslash escape sequences, if present, are decoded
   as follows:
          \a     alert (bell)
          \b     backspace
          \e     an escape character
          \f     form feed
          \n     new line
          \r     carriage return
          \t     horizontal tab
          \v     vertical tab
          \\     backslash
          \'     single quote
          \nnn   the eight-bit character whose value is  the  octal  value
                 nnn (one to three digits)
          \xHH   the  eight-bit  character  whose value is the hexadecimal
                 value HH (one or two hex digits)
          \cx    a control-x character

   The expanded result is single-quoted, as if the  dollar  sign  had  not
   been present.

即

$ python parse_input.py $'1\n2\n'