CODEWITHSUNDEEP
python
P_n
P_n

Reputation: 992

Python prevent decoding HEX to ASCII while removing backslashes from my Var

I want to strip some unwanted symbols from my variable. In this case the symbols are backslashes. I am using a HEX number, and as an example I will show some short simple code down bellow. But I don't want python to convert my HEX to ASCII, how would I prevent this from happening.? I have some long shell codes for asm to work with later which are really long and removing \ by hand is a long process. I know there are different ways like using echo -e "x\x\x\x" > output etc, but my whole script will be written in python. Thanks

>>> a = "\x31\xC0\x50\x68\x74\x76"
>>> b = a.strip("\\")
>>> print b
1�Phtv

>>> a = "\x31\x32\x33\x34\x35\x36"
>>> b = a.strip("\\")
>>> print b
123456

At the end I would like it to print my var:

>>> print b
x31x32x33x34x35x36

Upvotes: 0

Views: 1312

Answers (2)

che
che

Reputation: 12273

There are no backslashes in your variable:

>>> a = "\x31\xC0\x50\x68\x74\x76"
>>> print(a)
1ÀPhtv

Take newline for example: writing "\n" in Python will give you string with one character -- newline -- and no backslashes. See string literals docs for full syntax of these.

Now, if you really want to write string with such backslashes, you can do it with r modifier:

>>> a = r"\x31\xC0\x50\x68\x74\x76"
>>> print(a)
\x31\xC0\x50\x68\x74\x76
>>> print(a.replace('\\', ''))
x31xC0x50x68x74x76

But if you want to convert a regular string to hex-coded symbols, you can do it character by character, converting it to number ("\x31" == "1" --> 49), then to hex ("0x31"), and finally stripping the first character:

>>> a = "\x31\xC0\x50\x68\x74\x76"
>>> print(''.join([hex(ord(x))[1:] for x in a]))
'x31xc0x50x68x74x76'

Upvotes: 1

Uli Sotschok
Uli Sotschok

Reputation: 1236

There are two problems in your Code.

First the simple one: strip() just removes one occurrence. So you should use replace("\\", ""). This will replace every backslash with "", which is the same as removing it.

The second problem is pythons behavior with backslashes:

To get your example working you need to append an 'r' in front of your string to indicate, that it is a raw string. a = r"\x31\xC0\x50\x68\x74\x76". In raw strings, a backlash doesn't escape a character but just stay a backslash. 

>>> r"\x31\xC0\x50\x68\x74\x76"
'\\x31\\xC0\\x50\\x68\\x74\\x76'

Upvotes: 1

Related Questions