I have been seeing the same issue discussed in Issue #111

on a linux (Ubuntu 16.04 on a Mac Mini box) system. Since #111 focused on the Windows platform, it was recommended that a new issue be opened for linux.

What I have found is the when editing and saving a file on the circuitPython device, I often get a "syntax error" the first time I try to execute the saved script.

With guidance from @dhalbert here are a few consistent observations:
The problem only occurs if sufficient time is not allowed after saving the file and executing it.
It also depends on the editor used to save the file.
Using "gedit" I found that I had to wait ~30 seconds after saving the file before rebooting and executing it to reliably avoid the syntax error. I tried several delay times and found anything less than 30 seconds to be unreliable.
Using "nano" to edit the file, I was unable to cause the error no mater how quickly I rebooted.

One other note is that the problem did not occur at all with a very short (~300 byte) script. This is consistent with the discussion in #111

These tests were executed with CirCuitPython 2.0.0-beta-1.4 on a Metro_M0_Express - with a Jewel(7 Neopixel) connected to D2

Here is an example of the syntax error and the script.

Press any key to enter the REPL. Use CTRL-D to reload.

Adafruit CircuitPython 2.0.0-beta.1-4-gf6a7025 on 2017-08-11; Adafruit Metro M0 Express with samd21g18

import jewel_rainbow
Traceback (most recent call last):
File "", line 1, in
File "jewel_rainbow.py", line 45
SyntaxError: invalid syntax

# Gemma IO demo - NeoPixel
 
from digitalio import *
from board import *
import neopixel
import time
 
pixpin = D2
numpix = 7
 
#led = DigitalInOut(D13)
#led.direction = Direction.OUTPUT
 
strip = neopixel.NeoPixel(pixpin, numpix, brightness=0.3,auto_write=False)
 
 
def wheel(pos):
    # Input a value 0 to 255 to get a color value.
    # The colours are a transition r - g - b - back to r.
    if (pos < 0):
        return (0, 0, 0)
    if (pos > 255):
        return (0, 0, 0)
    if (pos < 85):
        return (int(pos * 3), int(255 - (pos*3)), 0)
    elif (pos < 170):
        pos -= 85
        return (int(255 - pos*3), 0, int(pos*3))
    else:
        pos -= 170
        return (0, int(pos*3), int(255 - pos*3))
 
def rainbow_cycle(wait):
    for j in range(255):
        for i in range(len(strip)):
            idx = int ((i * 256 / len(strip)) + j)
            strip[i] = wheel(idx & 255)
        strip.show()
        time.sleep(wait)
 
try:
    while True:        
        rainbow_cycle(0.001)

except:
    pass

finally:
    for i in range(len(strip)):
        strip[i] = (0,0,0)
    strip.show()