Bash: Looping urls using curl, giving only first url output - bash

Question

What I want to do: I want to find all the products(URLs) which are not redirected.
To get the final URL after redirection I'm using curl command as follows:
curl -Ls -o /dev/null -w %{url_effective} "$URL"
This is working fine. Now I want to iterate over URLs to get which are the URLs that are not redirected and display them as output of program. I've the following code:
result=""
productIds=$1
for productId in $(echo $productIds | sed "s/,/ /g")
do
echo "Checking product: $productId";
URL="http://localhost/?go=$productId";
updatedURL=`curl -Ls -o /dev/null -w %{url_effective} "$URL"`
echo "URL : $URL, UpdatedUrl: $updatedURL";
if [ "$URL" == "$updatedURL" ]
then
result="$result$productId,";
fi
done
The curl command works only for the first product. But from 2nd to last product, all the URL and updatedURL are same. I can't understand the reason why? The productId is changing in every iteration, so I think it cannot be something related to caching.
Also, I've tried the following variant of curl also:
updatedURL=$(curl -Ls -o /dev/null -w %{url_effective} "$URL")
updatedURL="$(curl -Ls -o /dev/null -w %{url_effective} "$URL")"
Edit: After trying with debug mode and lot of different ways. I noticed a pattern i.e. If I manually hit the following on terminal:
curl -Ls -o /dev/null -w %{url_effective} "http://localhost/?go=32123"
Then in shell script these urls will work fine. But if I don't hit manually then curl will also not work for those products via shell script.

Answer 1

Just add #!/bin/bash to be the first line of shell. It does produce required output. Now invocation should be like this bash file.sh 123,456,789,221
Invocation via Bourne shell sh file.sh 123,456,789,221 does requires code changes.Do let me know if you require that too :)

Answer 2

I would suggest changing your loop to something like this:
IFS=, read -ra productIds <<<"$1"
for productId in "${productIds[#]}"; do
url=http://localhost/?go=$productId
num_redirects=$(curl -Ls -o /dev/null -w %{num_redirects} "$url")
if [ "$num_redirects" -eq 0 ]; then
printf 'productId %s has no redirects\n' "$productId"
fi
done
This splits the first argument passed to the script into an array, using a comma as the delimiter. The number of redirects is stored to a variable. When the number is zero, the message is printed.
I have to admit that I can't see anything inherently broken with your original approach so it's possible that there is something extra going on that we're not aware of. If you could provide a reproducible test case then we would be able to help you more effectively.