This script removes lines with "0.0.0.0" or "127.0.0.1" at the beginning of the line. Useful for DNS-Blocklists.

Get file:

$ wget https://bytesofprogress.net/resources/bash-tools/cleanup/cleanup.sh

Contents of file: 

#!/bin/bash

INPUTFILE="input.txt"
OUTPUTFILE="output.txt"

# Does file exist?
if [ ! -f "$INPUTFILE" ]; then
    echo "ERROR: File $INPUTFILE does not exist!"
    exit 1
fi

# Removes lines with "0.0.0.0" or "127.0.0.1" at the beginning of the line.
sed -E 's/^(0.0.0.0|127.0.0.1)[[:space:]]+//g' "$INPUTFILE" | sort -u > "$OUTPUTFILE"

# Show line count before and after.
echo "Output saved as: $OUTPUTFILE"
echo "Original: $(wc -l < "$INPUTFILE") lines | Cleaned: $(wc -l < "$OUTPUTFILE") Lines."