diff --git a/port-jobs/COMMENTS.py b/port-jobs/COMMENTS.py
index a5969bd..1890576 100755
--- a/port-jobs/COMMENTS.py
+++ b/port-jobs/COMMENTS.py
@@ -1,23 +1,24 @@
 #!/usr/bin/env python3
 from os import listdir
-import re
+from re import match as rematch
 from sys import argv
 
 # read arguments
 arguments = argv[1:]
 
-# define regular expression depending on arguments
-if len(arguments) > 0 and arguments[0] == 'ALL':
-    regex = re.compile(r'^\s*#.*$\n?', re.MULTILINE)
-else:
-    regex = re.compile(r'^\s*# PORT.*$\n?', re.MULTILINE)
-
+# loop through all Python files in the working directory
 for filename in listdir('working'):
     if filename.endswith('.py'):
         filepath = 'working/' + filename
         # read input file
-        text = open(filepath, 'r').read()
-        # run the defined regular expression
-        new_text = re.sub(regex, '', text)
-        # write updated text
-        open(filepath, 'w').write(new_text)
+        with open(filepath, 'r') as file:
+            new_file = []
+            for line in file:
+                # determine whether to remove all or only PORT comments
+                if len(arguments) > 0 and arguments[0] == 'ALL':
+                    if not rematch(r'^\s*#', line):
+                        new_file.append(line)
+                elif not rematch(r'^\s*# PORT', line):
+                    new_file.append(line)
+        # write the updated file contents
+        open(filepath, 'w').writelines(new_file)