hoge.sh

#!/bin/bash

# $HOME/accountsにgithubのユーザー名を行区切りで書いておく
# accountsファイルは空行可、先頭に#でコメントが書ける

set -eu

pushd "$HOME"

test -r accounts
test -w .ssh/authorized_keys

if [[ ! -f authorized_keys_origin ]]; then
    cp .ssh/authorized_keys authorized_keys_origin
fi

for username in $(grep -v '^#' accounts); do
    echo "https://github.com/${username}.keys"
done | xargs curl --silent >> .ssh/authorized_keys

popd