Python 2/3 script to list unused variables from gfortran compiler messages

xunused_gfortran.py

# 2018-06-23
# list unused variable from gfortran output
# valid Python 2 and Python 3
from sys import argv
compiler_message_file = argv[1] # produced by command such as gfortran 2> err_msg.txt -c -Werror=unused_variable source.f90
fp = open(compiler_message_file,"r")
err_str = "Error: Unused variable"
print("unused variables:")
for line in fp:
    text = line.strip()
    if err_str in text:
        print(text.strip(err_str).split()[0].strip("'"))