How to convert 'binary string' to normal string in Python3?

For example, I have a string like this(return value of subprocess.check_output):

>>> b'a string'
b'a string'

Whatever I did to it, it is always printed with the annoying b' before the string:

>>> print(b'a string')
b'a string'
>>> print(str(b'a string'))
b'a string'

Does anyone have any ideas about how to use it as a normal string or convert it into a normal string?

Decode it.

>>> b'a string'.decode('ascii')
'a string'

To get bytes from string, encode it.

>>> 'a string'.encode('ascii')
b'a string'

If the answer from falsetru didn't work you could also try:

>>> b'a string'.decode('utf-8')
'a string'

Please, see oficial encode() and decode() documentation from codecs library. utf-8 is the default encoding for the functions, but there are severals standard encodings in Python 3, like latin_1 or utf_32.