Here's an example bash script that achieves your objective:

#!/bin/bash

# Download the text file from the given URL
wget -O temp_file.txt <url>

# Remove all lines starting with #
sed -i '/^\#/d' temp_file.txt

# Treat every line of the file as a URL and download them all to a single file
while read url; do
    wget -qO- "$url" >> output_file.txt
done < temp_file.txt

# Return success message
echo "All URLs downloaded and appended to output_file.txt"

To execute Task 2 and remove all lines starting with # from the temporary file, you can add the following line after the first wget command:

sed -i '/^\#/d' temp_file.txt

This uses the sed command to remove all lines that begin with the # character. The updated script will download the text file from the given URL, remove all lines starting with #, and then download all the remaining URLs to a single file called output_file.txt.
spam fails_task lang_mismatch pii not_appropriate hate_speech sexual_content quality toxicity humor helpfulness creativity violence