Reset time on ssh login in a Unix system

reset_time_on_ssh_login.sh

########################################
# Reset time on login                  #
########################################

# you may try to use system last logged time: `last ${USER} -n1 | head -1 | awk '{print $4" "$5" "$6" "$7}'`

time_sync_command='sudo ntpdate -s time.nist.gov'

# max time not logged value
not_logged_max_time_h=6
if ! [[ -f ~/.last_login_time ]]; then
    date > ~/.last_login_time
fi

# calculation
((last_time=$(date --date="$(cat ~/.last_login_time)" +%s), \
current_time=$(date --date="$(date)" +%s), \
tdiff=current_time-last_time, last_login_diff=tdiff/3600))

if [[ ${last_login_diff} -ge ${not_logged_max_time_h} ]]; then
    echo 'Time sync (.bashrc)...'
    ${time_sync_command}
fi

date > ~/.last_login_time

For vagrant, please update Vagrantfile with following:

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
...
  # Sync up time with servers
  config.vm.provision(
    :shell,
    :inline => 'sudo ntpdate -s time.nist.gov && echo "VM time is up-to-date." || echo "ERROR: Cannot sync time." > /dev/stderr',
    run:    'always')
...
end