諸事情により他人の権限でaptを叩くことになりました

pa

#!/bin/bash

# package agent script
# you can run apt command by other user's permission.

set -e

PASSWORD_FILE=$HOME/.pa/password
USERNAME_FILE=$HOME/.pa/username

function gen_password_file {
        echo "Initialize user information"
        echo "password and username file will be placed in ~/.pa"
        read -p "management user: " management_user
        read -p "password for $management_user: " -s password
        echo
        read -p "encryption key: " -s encryption_key
        echo

        mkdir -p $HOME/.pa
        echo $management_user | openssl des-ede3-cbc -e -k "$encryption_key" > $HOME/.pa/username
        echo $password | openssl des-ede3-cbc -e -k "$encryption_key" > $HOME/.pa/password
}

function get_userinfo {
        if [ -n "$encryption_key" ]; then
                decryption_key=$encryption_key
        else
                read -p "decryption key: " -s decryption_key
                echo
        fi
        exec_user=`cat $USERNAME_FILE | openssl des-ede3-cbc -d -k "$decryption_key"`
        password=`cat $PASSWORD_FILE | openssl des-ede3-cbc -d -k "$decryption_key"`
}

function auto-apt-get {
        if [ -z "$decryption_key" ]; then
                get_userinfo
        fi
        expect -c "
        set timeout -1
        spawn su -c \"sudo apt-get $@\" $exec_user
        expect \"Password:\"
        send \"$password\n\"
        expect \"password for $exec_user:\"
        send \"$password\n\"
        interact
        "
}

function show_help {
        echo "usage: pa [<action> [<package>]|<package>]

action:
        update system with no augument.
        f: fix package tree
        u: update system 
        i <package>: install <package>
        s <package>: seach <package>

example:
        pa
                update system
        pa f
                fix package tree
        pa i emacs
        pa emacs
                install emacs
        pa s emacs
                search emacs from package tree

* password and username file are placed in ~/.pa
"
}

if [ ! \( -f $PASSWORD_FILE -a -f $USERNAME_FILE \) ]; then
        gen_password_file
fi

if [ $# -eq 0 ]; then
        echo "[update system]"
        auto-apt-get update
        auto-apt-get dist-upgrade -y
elif [ $# -eq 1 ]; then
        case "$1" in
        f )
                echo "[fix package tree]"
                auto-apt-get install -f
        ;;
        u )
                echo "[update system]"
                auto-apt-get update
                auto-apt-get dist-upgrade -y
        ;;
        ??* )
                echo "[install package] $1"
                auto-apt-get install $1 -y
        ;;
        * )
                show_help
        ;;
        esac
elif [ $# -eq 2 ]; then
        case "$1" in
        i )
                echo "[install package] $2"
                auto-apt-get update
                auto-apt-get install $2 -y
        ;;
        s )
                echo "[search package] $2"
                apt-cache search $2
        ;;
        * )
                show_help
        ;;
esac
fi