# Buggy code
def p_subproc_arg_part(self, p):
    """subproc_arg_part : NAME
    | TILDE
    | PERIOD
    | DIVIDE
    | MINUS
    | PLUS
    | COLON
    | AT
    | ATDOLLAR
    | EQUALS
    | TIMES
    | POW
    | MOD
    | XOR
    | DOUBLEDIV
    | ELLIPSIS
    | NONE
    | TRUE
    | FALSE
    | NUMBER
    | STRING
    | COMMA
    | QUESTION
    | DOLLAR_NAME
    """
    # Many tokens cannot be part of this list, such as $, ', ", ()
    # Use a string atom instead.
    p[0] = p[1]


# Traceback (SyntaxError)
pip install django==1.9.9
...
xonsh: To log full traceback to a file set: $XONSH_TRACEBACK_LOGFILE = <filename>
Traceback (most recent call last):
File "/usr/local/lib/python3.5/site-packages/xonsh/__amalgam__.py", line 16237, in _parse_ctx_free
debug_level=(self.debug_level > 1))
File "/usr/local/lib/python3.5/site-packages/xonsh/parsers/base.py", line 314, in parse
tree = self.parser.parse(input=s, lexer=self.lexer, debug=debug_level)
File "/usr/local/lib/python3.5/site-packages/ply/yacc.py", line 331, in parse
return self.parseopt_notrack(input, lexer, debug, tracking, tokenfunc)
File "/usr/local/lib/python3.5/site-packages/ply/yacc.py", line 1181, in parseopt_notrack
tok = call_errorfunc(self.errorfunc, errtoken, self)
File "/usr/local/lib/python3.5/site-packages/ply/yacc.py", line 193, in call_errorfunc
r = errorfunc(token)
File "/usr/local/lib/python3.5/site-packages/xonsh/parsers/base.py", line 2355, in p_error
self.xonsh_code)
File "/usr/local/lib/python3.5/site-packages/xonsh/parsers/base.py", line 420, in _parse_error
raise err
File "<string>", line None
SyntaxError: <xonsh-code>:1:20: ('code: ==',)
![pip install django==1.9.9]
^

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/local/lib/python3.5/site-packages/xonsh/ptk/shell.py", line 99, in push
locs=None)
File "/usr/local/lib/python3.5/site-packages/xonsh/__amalgam__.py", line 16184, in compile
tree = self.parse(input, ctx, mode=mode, transform=transform)
File "/usr/local/lib/python3.5/site-packages/xonsh/__amalgam__.py", line 16155, in parse
tree, input = self._parse_ctx_free(input, mode=mode)
File "/usr/local/lib/python3.5/site-packages/xonsh/__amalgam__.py", line 16295, in _parse_ctx_free
raise original_error
File "/usr/local/lib/python3.5/site-packages/xonsh/__amalgam__.py", line 16237, in _parse_ctx_free
debug_level=(self.debug_level > 1))
File "/usr/local/lib/python3.5/site-packages/xonsh/parsers/base.py", line 314, in parse
tree = self.parser.parse(input=s, lexer=self.lexer, debug=debug_level)
File "/usr/local/lib/python3.5/site-packages/ply/yacc.py", line 331, in parse
return self.parseopt_notrack(input, lexer, debug, tracking, tokenfunc)
File "/usr/local/lib/python3.5/site-packages/ply/yacc.py", line 1181, in parseopt_notrack
tok = call_errorfunc(self.errorfunc, errtoken, self)
File "/usr/local/lib/python3.5/site-packages/ply/yacc.py", line 193, in call_errorfunc
r = errorfunc(token)
File "/usr/local/lib/python3.5/site-packages/xonsh/parsers/base.py", line 2355, in p_error
self.xonsh_code)
File "/usr/local/lib/python3.5/site-packages/xonsh/parsers/base.py", line 420, in _parse_error
raise err
File "<string>", line None
SyntaxError: <xonsh-code>:1:4: ('code: install',)
pip install django==1.9.9
^

# Fixed code
def p_subproc_arg_part(self, p):
    # Many tokens cannot be part of this rule, such as $, ', ", ()
    # Use a string atom instead. See above attachment functions
    p[0] = p[1]