GitHubに登録されたSSH公開鍵でログイン可能な同名のUNIXユーザを作成する。

append-github-user.sh

#!/bin/bash
set -eu

# デフォルトのパスワードが作成され ~/passwords.txt で保存されます。

if [ "$(id -u)" != "0" ]; then
        echo "please run as root"
        exit 1
fi

GITHUB_USERNAME="${1:-}"

if [ -z "$GITHUB_USERNAME" ]; then
        echo "USAGE: $0 GITHUB_USERNAME"
        exit 1
fi

USERNAME="$GITHUB_USERNAME"
DATETIME="$( date +"%Y/%m/%d %H:%M:%S" )"

PUBLIC_KEYS="$( echo "# $GITHUB_USERNAME ($DATETIME)"; \
        curl -s "https://api.github.com/users/$GITHUB_USERNAME/keys" | \
        jq -r '.[]|.key+" '$GITHUB_USERNAME'@github/"+(.id|tostring)' )"

echo "$PUBLIC_KEYS"
PASSWORD=$(openssl rand -base64 64 | perl -E 'local $/; $_=<>; s#\n#_#g;s#/#.#g;s#/#!#g; for my $c(1..16) { print substr($_,$c,1_) }; say ""')

useradd -m -s /bin/bash $USERNAME
echo "$USERNAME:$PASSWORD" | chpasswd
echo "仮パスワード: $PASSWORD" > /home/$USERNAME/password.txt
chown $USERNAME /home/$USERNAME/password.txt
chmod 600 /home/$USERNAME/password.txt
mkdir -m 0700 /home/$USERNAME/.ssh
chown $USERNAME:$USERNAME /home/$USERNAME/.ssh
touch /home/$USERNAME/.ssh/authorized_keys
chmod 0600 /home/$USERNAME/.ssh/authorized_keys
chown $USERNAME:$USERNAME /home/$USERNAME/.ssh/authorized_keys
echo "$PUBLIC_KEYS" > /home/$USERNAME/.ssh/authorized_keys