A linux shell proxy set/unset script

proxy-settings-for-linux-shell.sh

# Save following lines as '/usr/local/sbin/ssr-on'
# Enable proxy using command: . ssr-on
proxy_list=(
    http://username:passwd@192.168.1.2:1080
    http://192.168.1.11:1080
)
for proxy in ${proxy_list[@]}; do
    ip_addr=$(echo $proxy | sed -re 's|^http://||g;s|.*@||g;s|:[0-9]*/?$||g')
    port=$(echo $proxy | awk '{port=gensub(/.*:([0-9]{1,5})\/?/,"\\1","g",$0);print port}')
    nc -vz -w 1 $ip_addr $port &> /dev/null && {
        export http_proxy=$proxy HTTP_PROXY=$proxy https_proxy=$proxy HTTPS_PROXY=$proxy
        git config --global http.proxy $proxy
        echo "Proxy Server Set to $proxy" && return
    }
done
echo "No Alive Proxy Server Found!"
# to set proxy for apt update, see: 
# /etc/apt/apt.conf.d/87proxy # reference: https://askubuntu.com/a/920242/1410764



# Save following lines as '/usr/local/sbin/ssr-off'
# Disable proxy using command: . ssr-off
unset http_proxy https_proxy HTTP_PROXY HTTPS_PROXY
git config --global --unset http.proxy
echo "Proxy Server Dismissed!"

wget supports lowercase http_proxy only, and docker uses uppercase.
So it is recommended to set both upper and lower cases...
Reference: https://unix.stackexchange.com/a/212972/525088