regex - Python: 'q)+' is not recognized as an internal or external command -

python newbie here.

i have program named zeroormore.py

it reads regular expression (regex) stdin.

i invoke program this:

python zeroormode.py (ab)*(p|q)+ 

that results in error message:

'q)+' not recognized internal or external command, operable program or batch file. 

i discovered if enclose regex in double quotes:

python zeroormode.py "(ab)*(p|q)+" 

then there no error.

is there way accomplish without wrapping regex in double quotes? here's how program inputs regex:

regex = sys.argv[1] 

this isn't python; it's cmd. regex you're giving python being interpreted command prompt first. pipe (|) batch command piping input following program. basically, cmd reading command line so:

python zeroormode.py (ab)*(p    |    q)+ 

it's trying take result of running zeroormode.py (i think meant more?) (ab)*(p , piping output (nonexistent) program q)+.

there isn't of solution this, unfortunately. escape pipe so:

python zeroormode.py (ab)*(p^|q)+ 

the caret (^) cause special meanings next character has ignored.