Steps

• Check & install the required tools.
• Enter the following command in bash.
  (replacing [UserName] with the actual username.)

Script

curl -s https://api.github.com/users/[UserName]/repos | grep "clone_url" | awk '{print $2}' | sed -e 's/"//g' -e 's/,//g' | xargs -n1 git clone

Required Tools

• curl
• awk
• grep
• sed
• xargs
• git

OS

• Unix-like