A dead simple utility to compare / diff HTTP headers.
# command
$ diff-headers file1.txt file2.txt
# file1.txt
accept-ranges: bytes
age: 203
cache-control: public,max-age=0,must-revalidate
server: Netlify
# file2.txt (lines without ":" are ignored)
HTTP/2 200
age: 103
content-type: text/html
last-modified: Sun, 18 Jan 2015 00:04:33 GMT
vary: Accept-Encoding,User-Agent
# output
===== file2.txt is missing the following headers from file1.txt
HEADER VALUE
accept-ranges bytes
cache-control public,max-age=0,must-revalidate
server netlify
===== file1.txt is missing the following headers from file2.txt
HEADER VALUE
content-type text/html
last-modified sun, 18 jan 2015 00:04:33 gmt
vary accept-encoding,user-agent
===== Differences in shared header values
HEADER file1.txt file2.txt
age 203 103