multiple prints on the same line in Python

You can use the print statement to do this without importing sys.

def install_xxx():
   print "Installing XXX...      ",

install_xxx()
print "[DONE]"

The comma on the end of the print line prevents print from issuing a new line (you should note that there will be an extra space at the end of the output).

The Python 3 Solution
Since the above does not work in Python 3, you can do this instead (again, without importing sys):

def install_xxx():
    print("Installing XXX...      ", end="", flush=True)

install_xxx()
print("[DONE]")

The print function accepts an end parameter which defaults to "\n". Setting it to an empty string prevents it from issuing a new line at the end of the line.