BASH- trouble pinging from text file lines - bash

Question

Have a text file w/ around 3 million URL's of sites I want to block.
Trying to ping them one by one (yes, I know it is going to take some time).
Have a script (yes, I am a bit slow in BASH) which reads the lines one at a time from text file.
Obviously cannot print text file here. Text file was created >> w/ Python some time ago.
Problem is that ping returns "unknown host" w/ every entry. If I make a smaller file by hand using the same entries the script works. I thought it may be a white space or end of line issue so tried addressing that in script. What could the issue possibly be?
#!/bin/bash
while read line
do
li=$(echo $line|tr -d '\n')
li2=$(echo $li|tr -d ' ')
if [ ${#line} -lt 2 ]
then
continue
fi
ping -c 2 -- $li2>>/dev/null
if [ $? -gt 0 ]
then
echo 'bad'
else
echo 'good'
fi
done<'temp_file.txt'

Answer 1

Does the file contains URLs or hostnames ?
If it contains URLs you must extract the hostname from URLs before pinging:
hostname=$(echo "$li2"|cut -d/ -f3);
ping -c 2 -- "$hostname"

Answer 2

Ping is used to ping hosts. If you have URLs of websites, then it will not work. Check that you have hosts in your file , example www.google.com or an IP address and not actual full website urls. If you want to check actual URLs, use a tool like wget and another tool like grep/awk to grab for errors like 404 or others. Last but not least, people who are security conscious will sometimes block pinging from the outside, so take note.

Answer 3

C heck if the file contains windows-style \r\n line endings: head file | od -c
If so, to fix it: dos2unix filename filename

Answer 4

I wouldn't use ping for this. It can easily be blocked, and it's not the best way to check for either ip addresses or if a server presents web pages.
If you just want to find the corresponding IP, use host:
$ host www.google.com
www.google.com is an alias for www.l.google.com.
www.l.google.com has address 209.85.149.106
www.l.google.com has address 209.85.149.147
www.l.google.com has address 209.85.149.99
www.l.google.com has address 209.85.149.103
www.l.google.com has address 209.85.149.104
www.l.google.com has address 209.85.149.105
As you see, you get all the IPs registered to a host. (Note that this requires you to parse the hostname from your urls!)
If you want to see if a URL points at a web server, use wget:
wget --spider $url
The --spider flag makes wget not save the page, just check that it exists. You could look at the return code, or add the -S flag (which prints the HTTP headers returned)