Script for convenient enabling/disabling proxy settings on your Mac OS machine.

proxy.sh

#!/bin/bash

NETWORK_SERVICE_NAME="Wi-Fi"

if [ "$#" -ne 1 ]; then
    echo "Argument missing [on/off]"
    exit 0
fi

if [ $1 == "on" ]; then
    networksetup -setwebproxystate "$NETWORK_SERVICE_NAME" on
    networksetup -setsecurewebproxystate "$NETWORK_SERVICE_NAME" on
    echo "Enabled proxy for $NETWORK_SERVICE_NAME"
elif [ $1 == "off" ]; then
    networksetup -setwebproxystate "$NETWORK_SERVICE_NAME" off
    networksetup -setsecurewebproxystate "$NETWORK_SERVICE_NAME" off
    echo "Disabled proxy for $NETWORK_SERVICE_NAME"
else
    echo "Argument invalid [permitted:on/off]"
fi

Usage:

1. Create file proxy with content from above code snippet
2. Place file in your usr/local/bin
3. Give this file permission to be executed chmod +x /usr/local/bin/proxy
4. Call it from your command line like this: proxy [on/off]