bash - add a variable to binary inside string - linux

Question

So I have a curl command in a bash script:
#!/bin/bash
curl -s 'http://eamorr.com/?' -H 'Host: eamorr.com' -H 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:36.0) Gecko/20100101 Firefox/36.0' --data-binary $'-----------------------------1024109981087242139340277850\r\nContent-Disposition: form-data; name="target"\r\n\r\n90210\r\n-----------------------------102410998108724213934027785--\r\n'
This works fine for me.
Now, instead of 90210, I would like to try 90211
#!/bin/bash
postcode=90211
curl -s 'http://eamorr.com/?' -H 'Host: eamorr.com' -H 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:36.0) Gecko/20100101 Firefox/36.0' --data-binary $'-----------------------------1024109981087242139340277850\r\nContent-Disposition: form-data; name="target"\r\n\r\n'$postcode'\r\n-----------------------------102410998108724213934027785--\r\n'
This won't work...
I think it's something to do with the $ in front of the --data-binary string? I tried dropping the $, but it wouldn't work.
I tried $(postcode), etc. to no avail

Answer 1

The problem is you now wrongly quote what follows the postcode. \r\n is not interpreted in single quotes, you need $'\r\n':
...'$postcode$'\r\n...

Answer 2

#!/bin/bash
postcode="90211"
curl -s 'http://eamorr.com/?' -H 'Host: eamorr.com' -H 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:36.0) Gecko/20100101 Firefox/36.0' --data-binary $"-----------------------------1024109981087242139340277850\r\nContent-Disposition: form-data; name=\"target\"\r\n\r\n$postcode\r\n-----------------------------102410998108724213934027785--\r\n"
using quotation is a good practice, and "'$postcode'" is actually '90211' not 90211