Quick scripts to toggle the FC corporate proxy on an Ubuntu machine

disable-proxy.sh

#!/bin/bash

# Remove proxy config from system environment.
sed -r -i.old '/https?_proxy/d' /etc/environment

# Remove proxy config from APT.
sed -i.old '/proxy/d' /etc/apt/apt.conf

# Stop CNTLM.
systemctl stop cntlm.service

# Remove flight centre specific config from time sync config.
sed -i.old '/flitech/d' /etc/systemd/timesyncd.conf

# Set proxy as disabled in dconf.
dconf write /system/proxy/mode "'none'"

# Notify user.
notify-send -i notification-network-disconnected 'Proxy disabled'

enable-proxy.sh

#!/bin/bash

# Start CNTLM.
systemctl start cntlm.service

# Add proxy config to system environment.
if ! grep -q http_proxy /etc/environment; then
  echo 'http_proxy="http://localhost:3128/"' >> /etc/environment
  echo 'https_proxy="http://localhost:3128/"' >> /etc/environment
fi

# Add proxy config to APT.
if ! grep -q proxy /etc/apt/apt.conf; then
  echo 'Acquire::http::proxy "http://localhost:3128/";' >> /etc/apt/apt.conf
  echo 'Acquire::https::proxy "http://localhost:3128/";' >> /etc/apt/apt.conf
fi

# Set ntp server to flight centre one in time sync config.
if ! grep -q flitech /etc/systemd/timesyncd.conf; then
  echo 'NTP=time.au.flitech.net' >> /etc/systemd/timesyncd.conf
fi

# Set proxy as enabled in dconf.
dconf write /system/proxy/mode "'manual'"

# Notify user.
notify-send -i notification-network-connected 'Proxy enabled'

Consider binding these to F keys in System Settings -> Keyboard -> Shortcuts -> Custom. You'll need to run them with sudo, so if you put the scripts in /home/user/bin, make the shortcut something like sudo /home/user/bin/enable-proxy.