#!/bin/bash

user="$1"
if [ -z "$user" ]; then
  echo >&2 "Usage: become <user>"
  exit 1
fi

PRINCIPAL=$(klist 2>/dev/null | sed -n 's/^Default principal: //p')
BECOME="$HOME/.become"
profile="$BECOME/$user"
[ -f "$profile" ] || profile="$BECOME/all"

exec sudo -H -u "$user" env BECOME_HOME="$HOME" PRINCIPAL=$PRINCIPAL /bin/bash --rcfile "$profile"