if condition in shell scripting based on 404 unauthorized error - shell

Question

Here is my shell script. I want to put a condition to my curl commands based on the status i get. I need help in grepping "Http/1.1 401 Unauthorized" from the first curl command. After that i need to put it in a condition if status is 401, execute 2nd and 3rd curl command. Pls help
STATUS="HTTP/1.1 401 Unauthorized"
read $STATUS
for ((i=1; i<=2000; i++)); do
curl -i -vs -X POST -D post.txt -H "$SESSION_TOKEN" -H "$AUTH_TOKEN" -H "Accept:$ACCEPT_HEADER" -H "Content-Type:text/plain" "http://$BASE_URI/api/$PLATFORM//$CHANNEL_ID/subscription" | grep -e "*Unauth*" >> post.txt
if [$STATUS]
then
curl -i -vs -X POST -D tmp.txt -H "Content-Type:text/plain" --data "$SECRET" -H "Accept:$ACCEPT_HEADER" -H "Connection:close" http://$BASE_URI/api/${PLATFORM}/authenticate >> tmp1.txt
SESSION_TOKEN=`grep SessionToken tmp.txt`
curl -i -vs -X POST -D tmp2.txt -H "$SESSION_TOKEN" -H "Content-Type:text/plain" -H "Content-Type:application/json" --data "{ \"username\":\"$USER_NAME\",\"password\":\"$PASSWORD\", \"rememberMe\":\"false\"}" http://$BASE_URI/api/web/users/authenticate >> data.json
AUTH_TOKEN=`grep Authorization tmp2.txt`
continue
fi
done

Answer 1

The proper solution :
res=$(curl -s -o /dev/null -w '%{http_code}\n' http://google.fr)
if ((res == 404)); then
echo "404 spotted"
fi
or
res=$(curl -s -o /dev/null -w '%{http_code}\n' http://google.fr)
if [[ $res == 404 ]]; then
echo "404 spotted"
fi
Check
man curl | less +/'^ *-w'

Answer 2

You have to capture the curl output and examine the status line:
output=$( curl -i ... )
if [[ $output == "$STATUS"* ]]; then
# I was unauthorized
else
# ...
fi
Be aware that [ (and [[ I use in my answer)
is not mere syntax, it is a command, and as such it requires a space between it and its arguments