/([global].*[n])((.*[n])*)([s#]*http-proxy-ports?=s?.*)/gm

12http-proxy-port=9000

sed -i -r 's/([global].*[n])((.*[n])*)([s#]*http-proxy-ports?=s?.*)/12http-proxy-port=9000/gm'
 ~/.subversion/servers

### The currently defined server options are:
###   http-proxy-host            Proxy host for HTTP connection
###   http-proxy-port            Port number of proxy host service
###   http-proxy-username        Username for auth to proxy service
###   http-proxy-password        Password for auth to proxy service
###   http-proxy-exceptions      List of sites that do not use proxy
###   http-timeout               Timeout for HTTP requests in seconds

[groups]
# group1 = *.collab.net
# othergroup = repository.blarggitywhoomph.com
# thirdgroup = *.example.com

### Information for the first group:
# [group1]
# http-proxy-host = proxy1.some-domain-name.com
# http-proxy-port = 80
# http-proxy-username = blah
# http-proxy-password = doubleblah
# http-timeout = 60

### Information for the second group:
# [othergroup]
# http-proxy-host = proxy2.some-domain-name.com
# http-proxy-port = 9000

### SSL certificate.  See details above for overriding security
### due to SSL.
[global]
# http-proxy-exceptions = *.domain.org, *.domain.com
# http-proxy-host = proxy.domain.com
# http-proxy-port = 8080
# http-proxy-username = defaultusername
# http-proxy-password = defaultpassword