getgists.sh

#!/usr/bin/env bash
programname=$0
authtoken=$1
username=$2
option=$3

function usage {
    echo "usage: $programname [authtoken] [username] [-a|-n]"        
    exit 1
}

if [ $# -lt 2 ]
then
  usage
fi

if [ -z $option ]; then
    option="-n"    
fi

response=$(curl -s -H "Authorization: token $authtoken" https://api.github.com/users/$username/gists)
last_created_at="${username}_last_created_at.txt"
if [ ! -f $last_created_at ]; then
    echo $response | jq '.[].created_at' | sort -n -k 1 | tail -n 1 > "$last_created_at"
    echo $response | jq '.[].files[].raw_url' | xargs curl
elif [ "$option" == "-n" ]; then
    last_created_dt=$(cat $last_created_at |  sed -e 's/^"//' -e 's/"$//')
    newgists=$(echo $response | jq --arg ld $last_created_dt '.[] | select(.created_at | . > $ld) | .files[].raw_url')
    if [ ! -z $newgists ]; then 
        echo $newgists | xargs curl 
        echo $response | jq '.[].created_at' | sort -n -k 1 | tail -n 1 > "$last_created_at"
    else
        echo -e "No new gist published by $username since $last_created_dt.\nTo get all public gists \n\nusage: $programname [authtoken] [username] -a"
    fi
elif [ "$option" == "-a" ]; then
    echo $response | jq '.[].files[].raw_url' | xargs curl
fi

get the latest published gist for any user.
Please install jq before running the script