RunAs

This directive allows you to configure EZproxy, running on Linux, to startup automatically when the system boots with a non-root account and still open ports below 1024.

RunAs is a position-independent config.txt directive that is available in EZproxy for Linux. The RunAs directive allows you to tell EZproxy to change from the root user to a non-privileged user, and optionally a different group. EZproxy switches to the account specified at its earliest opportunity, after it has opened all low ports on which it needs to listen, but before it actually starts any proxying work.

RunAs someuser
RunAs someuser:somegroup