compare string in bash

Question

I tried to write the following script to compare two HTML response headers, however i am hitting the else condition despite by printing the header stored in the variable $a I am getting the exact same value.

#!/bin/bash
echo
echo "Connecting to www.cloudflare.com...";
curl -Is "https://www.cloudflare.com/" > file1.txt;
a=$(cat file1.txt | grep Server);
echo "$a";
echo
echo "Connecting directly to www.amazon.com...";
curl -Iks "https://www.amazon.com/" > file2.txt;
b=$(cat file2.txt | grep Server);
echo "$b";
echo

if [ "$a" == "Server: cloudflare-nginx" ]; then
    echo "This connection is going via CloudFlare"
else
    echo "This connection is NOT going via CloudFlare"
    echo "$a"
fi

Do you have output for your script too? I seem to get lower-case response for server header. — sebasth
– sebasth, Commented Aug 10, 2017 at 22:41
@steeldriver - I was just posting my answer with suggested change as you posted this comment. — Deathgrip
– Deathgrip, Commented Aug 10, 2017 at 22:51

Deathgrip · Accepted Answer · 2017-08-10 22:56:15Z

2

The header lines being returned from the curl commands have a ^M before the newline. You could change the if to use a regex:

if [[ "$a" =~ "Server: cloudflare-nginx" ]]; then
    echo "This connection is going via CloudFlare"
else
    echo "This connection is NOT going via CloudFlare"
    echo "$a"
fi

You can also remove the \r by changing the line:

a=$(cat file1.txt | tr -d '\r' | grep '^Server:');

edited Aug 10, 2017 at 22:56

answered Aug 10, 2017 at 22:49

Deathgrip

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