diff --git a/linkulator b/linkulator
index 8a14292..6fc333d 100755
--- a/linkulator
+++ b/linkulator
@@ -252,22 +252,28 @@ def reply(owner, tstamp, post_id):
 
     comment = input("Enter your comment (or leave empty to abort): ")
 
-    if comment == "":
-        input("Reply aborted. Hit [Enter] to continue.")
-    else:
-        if os.path.exists(config.USER.datafile):
-            append_write = "a"  # append if already exists
+    while True:
+        if comment == "":
+            input("Reply aborted. Hit [Enter] to continue.")
+            break
+        elif not posts.is_valid(comment):
+            print("Please try again, that response contains invalid characters.")
+            comment = posts.rlinput("Enter your comment (or leave empty to abort):")
         else:
-            append_write = "w+"  # make a new file if not
-        with open(config.USER.datafile, append_write) as file:
-            timestamp = str(time.time())
-            file.write(timestamp + "|" + owner + "+" + tstamp + "|||" + comment + "\n")
+            if os.path.exists(config.USER.datafile):
+                append_write = "a"  # append if already exists
+            else:
+                append_write = "w+"  # make a new file if not
+            with open(config.USER.datafile, append_write) as file:
+                timestamp = str(time.time())
+                file.write(timestamp + "|" + owner + "+" + tstamp + "|||" + comment + "\n")
 
-        link_data.insert(
-            0, ["", username, timestamp, owner + "+" + tstamp, "", "", comment]
-        )
+            link_data.insert(
+                0, ["", username, timestamp, owner + "+" + tstamp, "", "", comment]
+            )
 
-        input("Reply added.  Hit [Enter] to return to thread.")
+            input("Reply added.  Hit [Enter] to return to thread.")
+            break
 
     view_thread(post_id)