A simple redirect resolver

Did you know that curl has an option to automatically follow HTTP redirects? Combined with the HEAD method, this can be used to quickly trace the end destination in a chain of redirecting URLs:

#!/bin/sh
(echo $1 && curl -LIs "$1" | grep '^Location' | cut -d' ' -f2) | cat -n

The meat of the work is in the curl options:

• -L: if redirected, issue an identical request to the new location.
• -I: issues a HEAD command, which allows the server to omit the body.
• -s: no progress bar of failure indication

The subsequent grep/cut/cat combo serve to dice up the headers that are sent back and turn them into a pretty list of redirect locations.