Share jailbroken iPhone's WiFi connection from USB tether to a Mac.

socks-proxy-iphone.sh

# A USB tether always make use of the 3G/4G connection of your iPhone.
# You can override this config by buying MyWi 8.0 for 20 bucks or
# do the following. :-)

# Skip to step 4 if you already have ssh set up.

# 1) Install OpenSSH from Cydia
# 2) ssh into your phone. default password is `alpine`.
# I use CCSystemInfo to access my iPhone's cellular IP address easily.

ssh root@{phone-ip-address}

# 3) Change root password.

passwd root

# 4) On your Mac, set up a SOCKSv4 proxy on port 8080.

ssh -D 8080 root@{phone-ip-address}

# 5) Set your USB tether interface to use the new SOCKS proxy.
# Networks.prefpane doesn't have advanced settings for USB tether interfaces.
# Bypass this by using networksetup.

sudo networksetup -setsocksfirewallproxy "iPhone USB" localhost 8080

# 6) Do a speedtest 

wget http://mirror.rackspace.com/archlinux/iso/2015.02.01/archlinux-2015.02.01-dual.iso

# Enjoy :-)