Python: Concate code to a single string

Using the code below, the code from a source file can be concatenated to a single string. This string however can still be printed and formates nicely on a JavaScript console. It returns a string variable `s' and requires two command line arguments.

# Usage:
# > python ~/path/to/script/multiline.py <name_of_ouput_variable>  

    filename = sys.argv[1]
    
    f = open(filename, "r")
    d = f.readlines()
    f.close()
    
    s = "var %s = " % sys.argv[2]
    s = s.strip()
    
    # s += '"' + "".join(d).replace("\n", "") + '";'

    cnt = 0
    n = len(d)

    # '\\n' is explicitly written to the 'source'-file such that
    # the JavaScript console can print the source code including line
    # breaks.
    for line in d:
        # First line.
        if cnt == 0:
            s += "\n" + '  "' + d[cnt].replace("\n", "") + '\\n"\n'
            cnt += 1
        # Inbetween lines.
        elif cnt > 0 and cnt < (n-1):
            s += '+ "' + d[cnt].replace("\n", "") + '\\n"\n'
            cnt += 1
        # Last line.
        else:
            s += '+ "' + d[cnt].replace("\n", "") + '"'